One of the most essential doctrines for a Christian understanding of the Trinity is eternal generation. When the equality of the Son with the Father was thrown into question in the fourth century, the church fathers turned to the doctrine of eternal generation not only to distinguish the Son from the Father but to ensure that the Son is understood to be equal with the Father. For these reasons, the doctrine of eternal generation became a cornerstone of the Nicene Creed, that standard bearer of Christian orthodoxy. But over the last several decades, evangelicals have gained a bad reputation for rejecting this doctrine. Even when evangelicals have affirmed it, they do not appear to understand why. Could it be that we do not really grasp what eternal generation is in the first place?

I want to invite you on an adventure into the mystery of this indispensable Christian doctrine. But instead of exploring eternal generation’s biblical warrant (see Simply Trinity: The Unmanipulated Father, Son, and Spirit for that exciting journey), we will take the road less traveled and press into this doctrine’s theological reasoning.

Let the adventure begin.

What Is Eternal Generation?

The word generation means “coming forth,” and with reference to the Trinity it refers to the Son’s coming forth from the Father’s essence. The concept takes us to the very heart of what it means for the Son to be a Son. He is eternally from the Father, which is why He is called Son. To be more specific, from all eternity, the Father communicates the one, simple, undivided divine essence to the Son.

At the risk of stating the obvious, a son is, by definition, one who is generated by his father—one who has his origin from his father. While we will point out dissimilarities between human and divine sonship soon enough, we cannot miss the one fundamental similarity: sonship means one is generated by a father. When the concept is applied to the Son of God—as it so often is by the authors of Scripture—it means in its most basic sense that He, as the eternal Son, is from His Father.

To clarify, to be from the Father does not refer to the incarnation, to Christ as Mediator; being sent by the Father to save may reflect eternal generation, but it in no way constitutes eternal generation. Instead, to be from the Father refers to the Son’s origin in eternity, apart from creation. Generation is between Father and Son, an eternal act, and not between the Trinity and creation, as if it were a temporal act. As we will learn, generation is internal to the triune God—ad intra, as we like to say in Latin, as opposed to external, ad extra. The Father’s sending His Son into the world on mission for the world reflects the Son’s eternal origin from the Father (generation), but that mission in no way constitutes His eternal relation of origin. The Son is generated (begotten) by the Father before all ages apart from the world, irrespective of creation. He is Son whether or not He is ever sent into the world; He is the eternal Son from the Father whether or not He ever becomes incarnate. It is the immanent Trinity that is in view, not the economic.

There is another term that conveys the concept of generation: begotten. Perhaps you’ve heard the word used when reading those long genealogies in the Bible: so-and-so begat so-and-so begat so-and-so. But John applies this language to Jesus as well, referring to Him as the only begotten Son of God (e.g., John 1:14, 18; 3:16, 18). This begotten language, however, long predates the King James Bible. Way back in the fourth century, the church fathers who wrote the Nicene Creed used it as well. For example, the Nicene Creed says, “We believe in . . . one Lord Jesus Christ, the only-begotten Son of God, begotten from the Father before all time.”

This is the One, undivided God we are talking about; therefore, for the Son to be begotten from the Father means that God is begotten from God, which is why the creed confesses the Son to be “true God from true God.” To confess the Son as true God from true God is not an overstatement since He is, we dare not forget, consubstantial with the Father. Consubstantial means the Son is equal to the Father in every way, from the same essence or substance as the Father, no less divine than the Father. But we can only affirm such coequality if the Son is begotten from the Father’s essence. For if the Son is not begotten from the Father, the divine essence cannot subsist (exist) in the Son.

Furthermore, generation alone is what distinguishes the Son as Son. There is not some other concept or function or activity in the Trinity that distinguishes the person of the Son from the person of the Father. Generation alone can, for it alone conveys the nucleus of sonship. That is no small point, because without generation, not only is there no Son, but there is no Trinity. As the Calvinist Baptist John Gill warns, “Without his eternal generation no proof can be made of his being a distinct divine Person in the Godhead.1 Without generation, we fall headfirst into Sabellianism, for what previously distinguished Son from Father is dissolved, and as a result the persons are conflated until there is no plurality of persons at all.

The Son is generated (begotten) by the Father before all ages apart from the world, irrespective of creation.

With the basic idea of generation in place, we must qualify Sonship in the Trinity lest we interpret it in a literalistic fashion, with a one-to-one correspondence to creaturely sonship. There are significant differences between a divine generation and a human one. Understanding these differences—what eternal generation is not—aids us in better understanding what eternal generation is. It also avoids legions of heresies. Let’s begin with this question: When is the Son generated by the Father?

When Is the Son Generated?

That’s a trick question if there ever was one. There is no “when.” Why? The short answer: our triune God is eternal. He is not bound by time but is timeless; He has no beginning. A succession of moments cannot apply to Him. He just is. That means the following question is most relevant:

Q: If God is timelessly eternal, what does that mean for the Son and His generation from the Father?

A: Unlike human generation, the Son’s generation is eternal. There never was a time when the Son was not, nor ever a time when the Son was not from the Father.

Or, as early church fathers like Gregory of Nyssa like to say, there is no “sometime” for the Son because He was not generated in time. “He exists by generation indeed, but nevertheless He never begins to exist.”2

It’s not as if God the Son did not exist but then came into existence at a point in time, created by the Father and therefore after the Father. That may describe how generation works in our human existence, but it cannot depict the Son’s generation. He is, says Nicaea, “begotten not created.” He is, we cannot forget, the eternal Son from the Father. If the divine essence subsists in Him, then He too shares in the attributes of deity, eternity being one of them. He is no creature, and if not a creature, then His generation cannot be temporal. The generation of the Son, Gregory of Nyssa said, “does not fall within time, any more than the creation was before time.”3

If the Son’s generation did fall within time, then not only is there a time when the Son was not, but there is a time when the Father was not Father. And if there was a time when the Father was not, then there was a time when the Trinity was not. As Athanasius points out, “If the Son is not proper offspring of the Father’s essence, but of nothing has come to be, then of nothing the Triad consists, and once there was not a Triad, but a Monad.”4

Furthermore, if He is Son because He is from the Father, then His sonship must be as eternal as the Father Himself, at least if He is begotten from the same essence as the Father. That is why the Nicene Creed stresses that the Son is “begotten from the Father before all time . . . begotten not created . . . through Whom all things came into being.” The generation within God is unlike any other; it is not susceptible to the limitations of time. The Son’s filial identity has no duration or succession of moments; it is timeless. Everlasting in nature, there never was a time when the Son was not begotten from the Father.

That may sound like a contradiction—how can someone be generated and eternal? It sounds like a contradiction because we know generation only within the experience of our own finitude. For the infinite, timelessly eternal deity, the confines of our finitude do not apply. Let’s not forget that whatever words are used of God—even scriptural words and metaphors—this is God we have in view, infinite and eternal, immutable, and everlasting. Language is, by definition, analogical in every way. The metaphor must then be adapted to the incomprehensible One, not vice versa. So too with generation. As Augustine says, since the generation of the Son is eternal, “one exists not as before the other, but as from the other.”5 The Son is not generated after the Father, which would make Him less than the Father, but the Son is generated from the Father and from all eternity.

One more thing: Scripture refers to the Son’s eternal origin from the Father with a variety of metaphors, including Radiance, Image, Wisdom, Word, and Ancient of Days (each of which I treat at length in Simply Trinity). But one we can consider here is truth. As Jesus Himself says, He is the truth (John 14:6). Was there ever a time when God the Father was without His Truth? The Arians of the fourth century said yes. With a look of terror on his face, the church father Athanasius ponders this bizarre scenario: “For if the Son was not before His generation, Truth was not always in God.” It is a sin to say such a thing, Athanasius concludes. That sin multiplies if we also say there was a time when the Image was not, for “God’s Image is not delineated from without, but God Himself hath begotten it; in which seeing Himself, He has delight. . . . When then did the Father not see Himself in His own Image?”6

Answer: never.

The Father always and forever has seen Himself in His own image. So yes, the Son is the image of the Father, but unlike images in our finite world, there has never been a time when the Son was not the image of the invisible God (Col. 1:15).

What’s Next?

Believe it or not, we have only scratched the surface of the mysterious but essential doctrine called eternal generation. Continue this adventure with me in the next article as we answer the question, How is the Son generated from the Father? The answer might just surprise you.

Editor’s Note: This post is part of a series on the Trinity and was originally published May 10, 2021. Next post.

  1. John Gill, Body of Divinity, 144. ↩︎
  2. Gregory of Nyssa, Against Eunomius 1.39 (NPNF2 5:94). ↩︎
  3. Gregory of Nyssa, Against Eunomius 1.26 (NPNF2 5:71). ↩︎
  4. Athanasius, Against the Arians 1.6.17 (NPNF2 4:316). ↩︎
  5. Augustine, Contra Maximinum 2.14; cf. Thomas Aquinas, Summa Theologiae 1a.42.3, emphasis added. ↩︎
  6. Athanasius, Against the Arians 1.6.20 (NPNF2 4:318). ↩︎

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