Good theology is an invitation to look deeper into the things we believe. When it comes to the most important doctrines, we have the advantage of a rich history of carefully crafted creeds and confessions to help us along the way. For example, we believe that God the Son is “eternally begotten, not made, without beginning, being of one essence with the Father.” What is eternal generation and how important is it?

Faith in Jesus as the Son of God is the very essence of being a Christian. “If anyone confesses that Jesus is the Son of God, God abides in him, and he in God,” says 1 John 4:15. We confess that Jesus is the Son of God in answer to the gospel message that “the Father has sent his Son to be the Savior of the world” (1 John 4:14). But once we have confessed that Jesus is the Son of God, we have good reason to ask ourselves how deep his sonship goes, or how far back it reaches.

The answer is that the sonship of the Son goes as deep as the depths of God; it goes all the way back into the very being of God. There was never a time when the Son was not the Son.

Are There Alternatives?

The alternatives are unacceptable. For example, if somebody said that Jesus wasn’t always the Son of God, but became the Son at some point during his life — say when the Holy Spirit descended on him, or at the transfiguration, or at the resurrection — that would be the crudest kind of adoptionism. It would limit sonship to a phase of Christ’s life, and cut it off before tracing it back into his essential or eternal being.

Or if somebody admitted that there had always been such a thing as the second person of the Trinity, but that this person wasn’t “the Son” until he became incarnate, that would also be cutting off sonship before it reached all the way back. On this account we would have Jesus the Son on our side of things, but over on God’s side there would be no sonship. But if sonship is only real on our side of things, and corresponds to nothing in the being of God, then how has God made himself known in the sending of the Son?

Eternally Sendable

When the New Testament tells us that the Father sent the Son (1 John 4:14; John 3:16; Galatians 4:4), it presupposes that the Father always had the Son with him, sendable, so to speak. The Son was always there with the Father; the one God has always been the Father, the Son, and the Holy Spirit. It is crucial for the depth of the biblical message of salvation that what we encounter in Christ is not just another event or arrangement, but that when we meet the Son, we meet one who “was in the beginning with God” (John 1:2), one who “was with the Father and was made manifest to us” (1 John 1:2).

This was the line of biblical thinking that was classically expressed in the fourth century in the Nicene Creed, which recognizes Jesus as God the Son and calls him “eternally begotten.” The word begotten now sounds old fashioned to most people, but it means “to come from a father.” It is the paternal parallel to the maternal word born: children are begotten of fathers and born of mothers.

By calling God the Son eternally begotten, the Christian tradition is making it clear that Christ’s sonship goes all the way back into the being of God. The Son belongs within that divine being, or essence; to put it in more relational and Trinitarian language, he is of one essence with the Father.

Why Use Terms Outside the Bible?

It might seem safer to restrict ourselves to purely biblical language, and not go any further than affirming that he is the Son. But after we have quoted the biblical language, the value of using a few key terms that are not drawn directly from the Bible is that we can use them to specify what we understand the Bible to mean.

That is exactly the step we take when we say that the Son is eternally begotten. We are specifying that when we say “Son,” we don’t mean just anything that might be associated with any kind of sonship. We don’t mean that this son is younger, or has a divine mother, or is under parental authority, for example.

Affirming his eternal begottenness shows that we are not freely associating every possible aspect of earthly sonship with the divine Son, but picking out this particular eternal relation with the being of God. The Son is from the Father: coeternally, coessentially, coequally. Eternal generation means we don’t bring all our ideas about sonship and apply them to him; we learn from the eternally begotten one what he means by calling himself the Son of God.

Why This Is Important

How important is eternal generation? Its fundamental value is that it tells the truth about who God the Son is according to Scripture. Even if it were a truth with no further practical implications, that would be enough, because confessing the Son’s eternal generation would help us keep our balance not just in christology but in everything we say about God the Son.

But it is also a doctrine with practical implications, mainly because of how closely connected it is to the doctrine of salvation. We have talked about the importance of tracing sonship all the way back into God in order to confess more accurately that Jesus is the Son of God. Grounding sonship in God’s own being, in the one who is “eternally begotten, not made, without beginning, being of one essence with the Father,” also means that our adoption is grounded in God.

When God saves sinners, he does so by coming to us in our extreme need and bringing us into his own life of blessedness and communion. God opens up the divine life to us without compromising his deity or obliterating our creaturehood, because God the Father sends God the Son and God the Holy Spirit to encompass us in the Father-Son-Spirit life that is our only possible source of salvation.

Adopted into an Eternal Sonship

The sonship into which we are adopted as human sons and daughters is a sonship that, in the person of God the Son, goes all the way back into God. What the second person of the Trinity is by nature, the redeemed become by grace: sons. There is a linked chain of sonship that is joined to God on one side and our salvation on the other. The only-begotten Son becomes the incarnate Son and brings about fellowship with adopted sons. The more clearly and surely we confess the eternal begetting of God the Son, the more deeply we will understand our regeneration as adopted sons.

The doctrine of eternal generation is a treasure of Christian theology. In addition to being a biblical truth, eternal generation also happens to be the deeply traditional position confessed by the church down through the centuries. And it reaches all the way down into the experience of salvation and the Christian life, which is a life of sonship grounded in the eternal depth of the eternal Son.