If the Son’s generation from the Father involves no priority, can we also say it involves no mutation?
The Son’s generation from the Father involves no change in God. In a sermon series on the Gospel of John, Augustine once said to his congregation, “Although changeable things are made through the Word, that Word is unchangeable.” God may create the changeable world through His Word, but remember, the Word Himself does not change. For He is not created but begotten from the Father’s nature from all eternity. The Son, Athanasius says, “being from the Father, and proper to His essence, is unchangeable and unalterable as the Father Himself.” Whereas a bodily begetting involves mutation, a begetting that is without a body (incorporeal) does not.
Remember, says the seventh-century church father John of Damascus, eternal generation means that the Son is “from the Father’s nature.” If He is from the Father’s nature, a nature that is not only simple and eternal but immutable (unchanging), then no change can occur in generation. If it does, then either the Father’s nature is not immutable or the Son is generated from another nature, external to the Father, and in that case could no longer be coequal to the Father in divinity.
In John Gill’s nine marks of an unhealthy generation, you may have noticed that five of them—motion, mutation, alteration, corruption, diminution—have one thing in common: they are all the result of change. This is inevitable with human generation, for where finite creatures are involved there is always change, and where there is change, we have the potential to change for the worse, which means corruption is a real possibility.
But not so with the triune God, whose nature is not only eternal but immutable. If immutable, then the Father begets His Son without alteration to the divine nature. That is because there is no potency in God, meaning God has no unactualized potential He must reach, as if He is not true God until He reaches His full potential. Instead, He is the perfect being, self-existent, self-sufficient, always and forever His perfect self, maximally alive, without any need to somehow become more perfect than He is for all eternity—which is why the fathers called Him pure act. The Father does not beget His Son as if the Son must somehow reach His potential over time, as if He must grow and change and become more perfect than He was before. Remember, the Trinity is perfect, maximally alive, never in need of becoming something more or greater or better. That means eternal generation “is a perfect generating perfect act.” Perfect generating perfect—that sounds a lot like Nicaea’s true God from true God.
All that to say, if the Son’s generation is eternal, so also it must be immutable. Where there is a succession of moments (time), change will follow; indeed, it must. But in eternity, there is no successiveness and therefore no mutation in God. The Father begets His Son not as a new moment in time but from eternity. To say, as the Nicene fathers did over against the Arians, that there never was a time when the Son was not is to also confess there never was a time when the Son was not immutable. If He was not begotten out of the eternal, immutable nature of the Father, then we would be right to ask whether something is lacking in God, whether God Himself is incomplete and imperfect.
But we can rejoice with Thomas Aquinas, who says:
The Father’s nature has been complete from all eternity; the action whereby the Father brings forth the Son is not successive, because then the Son of God would have been begotten in stages and his begetting would have been material and involved movement. All impossible consequences. What remains, then, is that whenever the Father was, the Son also was and so is co-eternal with the Father, as also is the Holy Spirit with them both.
May the Adventure Continue
I’m afraid our adventure must end. But your adventure has only just begun. For the Trinity, after all, is a marvelous mystery, summoning many a Christian wayfarer to explore its infinity glory. Before I leave you, I’m afraid I must warn you. Along the way, you will meet some who dismiss this Christian doctrine called eternal generation. Others will join you on your journey, but as your pilgrimage continues, you will find they misuse, even manipulate this Christian doctrine for their own agenda. But if you remain faithful, you will reach the blessed land of the Trinity, and there your theology will turn into doxology.
Editor’s Note: This post is part of a series on Bible study. Previous post.