"If you want to judge how well a person understands Christianity," wrote G.I. Packer in his famous book, Knowing God, "find out how much he makes of the thought of being God's child and having God as his father. If this is not the thought that prompts and controls his worship and prayers and his whole outlook of life, it means that he doesn't understand Christianity very well at all." That is powerful.

A Christian is one who has been adopted by God, brought into the family of God, all by the Son of God. And this changes everything. To better understand how precious it is to be a son of God, we need to pay attention to our Bibles, especially as we see the theme of sonship as it unfolds throughout the biblical storyline from Genesis to Revelation and to that end.

I called up Dr. Don Carson, the co-founder and president of the Gospel Coalition, and he is also the editor of the NIV Zondervan Study Bible, which is sort of a study Bible version of what we're doing in these podcasts. Here's how Dr. Carson explained to me the theme of sonship as it develops in the Bible from Genesis to Revelation.

Even a cursory reading of Scripture shows how the expression "Son of God" can refer to many, many different people. In fact, it stretches beyond people. It can refer to angels in the opening chapters of Job. The term "Son of God" can refer to Israel, considered collectively. That shows up for the first time in Exodus chapter 4.

"Out of Egypt I called my son," Hosea says, referring to the Exodus. And already in Exodus chapter 4, God says, "Israel is my firstborn son." And I say, "Let my son go that he may worship me." Then "son" can refer to individual Israelites, "Son of God." And in addition, it can refer to the king, Paracelos, starting as early as 2 Samuel chapter 7.

The son of God is the Davidic king. And in addition, in the New Testament, it can refer to Christians. And of course, supremely, it can refer to Jesus. So all of these expressions use "Son of God" to refer to a variety of human beings, and even angels. So what is meant by the expression?

Clearly, you cannot simply assume that every time you come across the expression "Son of God," it's referring to the second person of the Godhead. It's important to back off a wee bit, I think, and remember that connotations of sonship, not just "Son of God," but of sonship, were different in the ancient world than the kinds of associations that the expression calls to mind today.

Today, people watch various CIS programs on television, and not a few plots are bound up with who is really the father and who is really the son, and it's tested by DNA or some other contemporary technological marvel. And yet, that's not the association of sonship. Sonship is not established by paternity in the Old Testament.

The overwhelming majority of sons in the ancient world ended up doing vocationally what their fathers did, and of girls ended up doing vocationally what their mothers did. So if your father's a baker, you end up with overwhelming likelihood becoming a baker. If your father's a farmer, you become a farmer.

If your father's a candlestick maker, you become a candlestick maker. And thus, sonship is bound up in part with family identity and vocation. That's why Jesus is often referred to as the "son of a carpenter," and that's because he's identified as belonging to the Joseph family. In one remarkable passage in Mark 6, he's referred to as the carpenter.

Apparently, Joseph has died, and Jesus, for a period of time before he entered his public ministry, took over the family business. If your father's a farmer, you don't go away to agricultural college and then come home and help the old man. There were no such things as agricultural colleges.

The father showed you how to dig fence posts, and how to irrigate, and when to seed, and how to go about the business of harvesting, and how to read the soil, and read the weather, and so on. You, with us, received your family name, your identity, your vocation, your inheritance, and so on, all bound up with what you do.

And out of this, then, comes a wide variety of metaphors in the Bible. "Sons of Belial" Belial means something like "worthless." If somebody calls you a son of Belial, it's not really meant to be an insult to your father. It's saying that you, yourself, are acting so much like a worthless person that you must be thought of as belonging to the worthless family.

And Jesus, likewise, in the Beatitudes says, "Blessed are the peacemakers, for they shall be called the sons of God." Literally. Not children of God, sons of God. Referring to both men and women, of course. But the metaphor itself is powerful. What it's saying is that God is the supreme peacemaker, and insofar as we are making peace, we show ourselves to belong to the God family.

It's not talking about ontology. It's not talking about how you become a Christian. It's that if you act like God, you're Goddish. And one of the ways of saying that is that you're son of God. And that explains quite a lot of passages in the New Testament that we sometimes glance over and don't integrate into our thinking.

For example, in John 8, the Jews in dispute with Jesus claim that they are really the sons of Abraham. And Jesus says, "Oh, no, that can't be. Abraham rejoiced to see my day. He sought and was glad." You can't really be sons of Abraham at all. And they up the ante and say, "Well, actually, we're sons of God." And he says, "No, that can't be, because God knows me and I know him.

You don't recognize me. You can't really be sons of God at all. Let me tell you who your daddy is." And he says, "You are of your father the devil, and the lust of your father you will do." Now, he is not suggesting in any way, shape, or form that they're sons of miscegenation, as if demons somehow copulated with women to produce them.

It means they're acting so demonically that they belong to the demon family. They're sons of the devil himself. And likewise, in Paul, the question arises frequently, "Who is the true son of Abraham?" And the true son of Abraham is not the one who has Abraham's genes, but the one who acts like Abraham.

And Abraham acted with respect to God in faith. So he becomes the father of the faithful, that is, those who are full of faith. The true son of Abraham is the one who has Abraham's faith, not the one who has Abraham's genes. And that sort of usage is simply endemic in Scripture, sometimes using metaphors that aren't even preserved in English translation because they don't make sense in English.

But the son of metaphor is very common. And so, within that framework, then, what does "son of God" mean? Well, in a passage like 2 Samuel chapter 7 and Psalm 2, where the Davidic king is said to be son of God, the idea, of course, is that God is the supreme king.

So that insofar as someone is acting like God in ruling, God rules as king. He is the monarch. He's not a constitutional monarch. He reigns, he rules, and he rules with justice, with integrity, with righteousness, to preserve the covenant, with equity, and so forth. So, insofar, then, as his underking, his Davidic king, is king, then he is to rule the way God rules, with equity, with justice, with integrity, and speaking the truth, and so forth.

And if he does so, then he is, like God, he is God's son, insofar as rulership is concerned. So, as soon as Davidide accedes to the throne, then God says, in effect, "Today I have begotten you. Today you are my son." Again, it's not talking about new birth, it's not talking about ontology.

This is said with respect to Solomon, for example. And yet, so far as ruling is concerned, the Davidic king is to belong, to be seen to belong, to the God family, to rule like God, to be Goddish in that particular respect, just as the person who makes peace is like God along another axis, the peace axis.

So, in other words, you cannot assume that son of God refers to the Trinity, as the second person of the Trinity, or something like that. Now, there are some passages that drive you in that direction, we'll come to those in a few moments. What this means, then, is that in Old Testament expectation, sonship can refer to all of Israel, starting in Exodus 4, as we've seen, and picked up in passages like Hosea chapter 11, "Out of Egypt I called my son." And then, "Out of Egypt I called my son," in Hosea 11, is picked up in Matthew chapter 2 and applied to Jesus.

So he, too, is called back out of Egypt. And it's part of Matthew's way of indicating that, in some sense, Jesus recapitulates Israel. He is Israel's true focus. The same theme is picked up, for example, in the temptation narrative in Matthew chapter 4. In the desert, Israel is supposed to learn that man does not live by bread alone, but by every word that proceeds from the mouth of God.

They really don't learn it, they fall away. But Jesus learns it perfectly, and reflects it perfectly, and thus shows himself to be, in one sense, the true Israel. But he's also the true king. He's the true Davidic king. The very first verse of Matthew begins, "The origins of Jesus Christ, the son of Abraham, the son of David." And then the genealogy proceeds with 3/14, the central 14 being the years of the Davidic dynasty in actual rule.

So, he is repeatedly called the son of David, and in some passages, son of God overlaps with son of David quite remarkably. We'll refer to some more passages of that order shortly. In the Old Testament, likewise, in words that we sing every Christmas as we hum along to Handel's Messiah, words drawn from Isaiah 9, "Unto us a child is born, unto us a son is given.

He shall reign on the throne of his father David." So, he's the son that is declared son, in line with Psalm 2 and 2 Samuel 7, where God insists that the Davidic king thus is his son, insofar as he is acting like God as king, ruling with integrity and the like.

So, "Unto us a child is born, unto us a son is given. He will rule on the throne of his father David. And of the increase of his kingdom there will be no end. But extra things are said of him. He shall also be called the wonderful counselor, the mighty God, the everlasting father, the prince of peace." If that language is taken seriously, then he's more than an ordinary David-eyed, a son of David.

He is a son of David, a son of David because he's king, like all the other sons of David who are kings. But there's something more that is being promised to him, and the expectations of what this Davidic son of God would be like are ratcheted up. 2 Samuel 7 is roughly 1000 BC.

Isaiah 9 is toward the end of the 8th century. And then that language is picked up likewise in the New Testament. In the long passage in Hebrews chapter 1, verses 5 and following, the sonship that is in view for Jesus is first and foremost the Davidic sonship, as the particular passages that are quoted make clear.

And so the way that Jesus is superior to the angels in much of Hebrews chapter 1 is that he alone has the right to be the Davidic king who rules. Now, there's another element that we're coming to there that's stronger yet, but it really is important to see that Jesus is son of God by virtue of the fact that he's the Davidic king.

He's son of God by virtue of the fact that he's the ultimate Israel. There's another element, too. Adam is called the son of God. In the genealogy of Luke's gospel, we have these son of expressions. Who was the son of this? Who was the son of that? Who was the son of the other party?

Until we get to Adam, who was the son of God. And so it's not too surprising that human beings can be called sons of God in a generic sense, without necessarily being Christians. We're sons of God in that we're supposed to be God's image bearers. We're supposed to reflect him insofar as human beings can reflect him.

And again, the idea is not ontology, it's reflection of the one whom we call our heavenly father. And so Jesus is the ultimate Davidic king as the son of God, as the son of God is the ultimate Israel, as the son of God is the ultimate human being, too.

All of those expressions are applied to Jesus in a variety of ways. But there is another strand that does not fit into any of these categories. In the gospels, it's most powerfully drawn in John chapter 5, especially verses 16 and following. It's a wonderful passage. Jesus is defending his actions in the healing of the man who has been paralyzed for 38 years.

His actions on healing him on the Sabbath, and his actions in telling the man to roll up his mat and take it home. And he does not defend his actions by virtue of appeal to the intricacies of the law. He does not say, "Well, come on, the law does not really forbid miraculous healing." It's not as if I'm a medical practitioner who's opening his place for office hours on the Sabbath in order to earn a little extra pocket money.

That's not what's going on. He doesn't defend himself that way. What he says instead is that whatever God has the right to do, he's got the right to do. My father works till this day, and I, too, am working. And the interlocutors perceive, therefore, that he's making himself equal with God.

So he's doubly wrong, doubly blasphemous. He's working on the Sabbath, and he's making God his equal. And what they mean by him making God his equal is that somehow he is presenting himself as a second God. There is God, and then there's Jesus claiming to be God, and that's blasphemous.

So Jesus responds, then, by insisting that he does have the same prerogatives of God, but he presents his deity, his godness, in ways that still preserve monotheism. So he says in chapter 5, verse 19, that he does only what the Father gives him to do. He says only what the Father gives him to say.

In that sense, he's not a competing God. He's not God number two. He's not a parallel God. He's one with God in what he says and does. He can do nothing by himself. There's even some kind of dependence. I know in this day and age, people sometimes get themselves in a twist because they don't like the word "subordination." But, in fact, in John's Gospel, we discover again and again and again that Jesus does what the Father gives him to do.

He says what the Father gives him to say. It's never the other way around. This relationship is not equivalent. It is one way only. And if you don't like the word "subordination," then choose another. But you have to have some word to show that it is not an entirely reciprocal relationship.

But having said that, that he says only what the Father gives him to say, he does only what the Father gives him to do, and he does all that the Father does, becomes the really important thing. That's the direction to which he turns. That is, not only does he do only what the Father gives him to do, he does everything that the Father does.

Now, that is astonishing. Because when you and I use the expression "Son of God" because we're peacemakers, we're peacemakers only along the peace-- we're sons of God only along the peacemaking axis. When David, or one of his successors, is son of God because he's a Davidic king, he's a son of God along that reigning axis.

But Jesus says that whatever the Father does, the Son also does. Has the Father made everything? So has the Son. We've discovered that already in the first verses of John's Gospel. "In the beginning was the Word, and the Word was with God, and the Word was God." And he was with God in the beginning, and all things were made by him.

And without him was not anything made that was made. So he's one with the Father in creation. And by the end of the chapter, he's--down around verses 28 to 30-- he's one with the Father in judgment. Judgment, final judgment, belongs to God. But Jesus has it as well. In fact, Jesus' judgment is perfect because he judges only as the Father gives him to judge.

But the point is, I don't have the ultimate judging right that God has. Jesus has it. And whatever the Father does, the Son also does. In other words, Jesus claims coextensive action with God. So although this is cast in terms of conduct, behavior, functionality, nevertheless, you can't help but see there's an ontology behind it.

If you have a being who really can do everything that God does, who really says everything that God says, then how is he distinguished from God? If you have an animal that looks like a horse and walks like a horse and has all the attributes of a horse, you've got a horse.

And if you have a being who can say and do all that God says and does and reflects him perfectly and says only what he is given to say and so on, then how is he distinguished from God? And then when you discover in chapter 5 as well that the Father's determination is that all should honor the Son even as they honor the Father, the Son even as they honor the Father, you perceive that this Son is not Son in some restricted way in the fashion of David or Son in some restricted way in the fashion of the peacemaker.

He is to be honored as God is honored. And so you have the beginnings of the doctrine of the Trinity being spelled out in front of your eyes in passages of that order. And so when we return to Hebrews chapter 1 and discover that in chapter 1, verses 5 and following, Jesus is presented primarily as the Son of David.

And as he has the right to rule, he surpasses angels because they don't have the right to rule. Nevertheless, you have to read 1, 5 and following in the light of 1 to 4, the prologue of Hebrews. And there we're told that in times past God spoke to the fathers through the prophets in various ways and various manners and so on.

But in these last days, he has spoken unto us, or the Greek has, "en hwio," in his Son, in the Son. But the particular construction suggests that the emphasis is on the quality of this revelation. One might paraphrase, "In these last days, he has spoken unto us in the Son revelation." And then this Son revelation is described in spectacular ways.

Jesus is the radiance of his Father's glory. As someone has said, he's the shining of the shining. How do you distinguish those two? He radiates outwardly God, or he's the perfect stamp of God. He's the perfect reflection. It's stamped out so that he is God-ish through and through. And so he is identified as one with God, with all of the authority to uphold all things by his powerful word, yet at the same time is presented as the high priest who mediates God to us and us to God.

And so sonship here is being used in a way that outstrips any mere alignment with Davidic rule, or with Israel, or with ordinary human beings, or with peacemaking, or the like. He is God's perfect self-disclosure, the shining of the shining, the radiance of the glory. He is the Son par excellence.

This is the Son revelation. In the past God spoke through words alone. Now he speaks, as it were, through the Son. So theologically this becomes somewhat equivalent to John's prologue. "In the beginning was the Word, and the Word was with God, and the Word was God." That is, in the beginning God expressed himself, and the self-expression was with God, and the self-expression was God.

And so you have now the beginnings of a notion of sonship that is picked up in many passages in the New Testament to generate what is ultimately called the doctrine of the Trinity, with Father, Son, and Holy Spirit being three persons, but constituting one God. Nor is this sonship restricted to Jesus in the days of his flesh.

John 3.17 reminds us that God sent his Son into the world. That is, it's not he sent someone into the world who thus became his Son, by virtue of the fact that he became a human being and a Davidic king. He sent his Son into the world. This Father-Son relationship is traced back into eternity.

The Father sends his Son into the world. And that is not just a Davidic figure. The Davidic sonship didn't start, after all, until about a thousand years before Christ. And thus, sonship can have all of the deep, rich set of associations that are traditionally tied to the deepest, most thoughtful, biblically mandated doctrine of the Trinity.

But then, likewise, it's important to think how we Christians are sons of God. And in one sense, this is the result of the new birth, something working within us. That's another whole theme that needs a separate development. But in the climactic revelation of the Bible, Revelation 21 and 22, we're told that the overcomer, that is, the Christian who perseveres to the end, that's what's meant by overcoming, will be called God's Son.

Now, in one sense, he's been called God's Son again and again and again, implicitly referring to Israelites under the Old Covenant. Certainly, in the New Testament, various sonship words are used. In John's Gospel, one word is used for Jesus, the Son of God, and other words are used for human beings as sons of God, human beings who are not the human that Jesus is.

In Paul, both Jesus and Christians are called sons of God, the same word, but we're sons of God by adoption. Some sort of distinction is made. But the power of the metaphor itself, Son of God, is seen in its greatest power applied to Christians in Revelation 21 and 22.

"He will be my Son," God says. And what is meant in the context is, so much will He be like me that there is no longer any possibility of sin or death or corruption or decay or rebellion in the Christian who is thus called Son of God, whether men or women, called sons of God, because they reflect God as perfectly as finite human beings made in the image of God can.

There is no taint, there is no sign of death or decay. Their reflection of God is as perfect as it is possible for a finite human being to reflect the infinite God. Thus, the notions of sonship, even though they begin with a certain kind of emphasis on functionality and repeating the behavior of the Father in question and so on, eventually get tied to the most profound theology and the most demanding ethics as we worship the true Son of God in order that we may, on the last day, so be transformed by the Gospel in glorification that we act perfectly as sons of God in a way that we measure up to only very imperfectly until Jesus returns.

Amen. From his home office, that was Dr. Don Carson, the co-founder and president of the Gospel Coalition and the editor of the NIV Zondervan Study Bible, which is the Study Bible version of what we're doing in these podcasts, which is generally called Biblical Theology on occasional Fridays. I call him up and he explains one theme of Biblical Theology and we are working our way through about a dozen or so of the most important Biblical themes from Genesis to Revelation and a number of those to date can be found in the Ask Pastor John podcast archive online.

Well, by faith we are united to Christ and in Him we are drawn into the family of God. So what is the purpose and the point of all of this in the end? It's a really important question and John Piper will explain on Monday. I'm your host Tony Reinke.

Have a great weekend.