To talk about God, we can either start at Genesis and work our way forward (so God is Creator, is covenant maker, and is one) or we can start at the end and work our way backward (God is triune and has always been triune throughout the Bible). Since we have a full revelation of God in the Bible, the latter makes the best sense. We do not have to act as if the New Testament or Isaiah have yet to be written. They are there. God revealed himself fully by becoming human.
Starting at the end, we can know one of the most important things about God: he is life. And it is for this reason that he has come to save the world by giving it eternal life. Knowing that God is life, therefore, stands at the centre of everything for it not only reveals God’s nature to us, but it also explains why he has granted life to his creatures and has come to save us from sin and its consequence of death.
The Father gives life to the Son
Jesus reveals God to us (John 1:9, 18). And here is what he says of the Father: “the Father has life in himself” (John 5:26). The Father has life in himself. He exists. Existence belongs to him. Nothing exists apart from God who grants existence. And not just existence but life in himself.
The Father does not keep life in himself. It is in him to share all that he has. The fuller context of Jesus’ words reads: “For as the Father has life in himself, so he has granted the Son also to have life in himself” (John 5:26). The Son has no existence apart from the Father. Only through the Father does the Son have existence. The one grants it to the other. yet both have it.
Nothing outside of the Son gave him life; the Father alone did as the Father alone possesses life in himself. But he shares that life with his Son. For this reason, the Son too has life in himself.
The life in God is his relations
Since God has life in himself, he has no need for outside support. He has his being from himself or in himself. Theologians call this aseity. In Latin, a means “from” while se means “self.” God has life from himself.
Yet this doctrine by no means signifies some dry reality that God is not his creation and so is distinct. Certainly, that is an implication. But that is a modern emphasis in theology. The older ways are much more vibrant.
God’s aseity means that he has life in his trinitarian relations. As John Webster has written, “Aseity is life” (2016: 19). The Father eternally generates the Son. He eternally, always, and outside of when and where gives the Son life in himself. The Spirit likewise spirates from the Father through the Son. The Spirit too gives life (John 6:63). The Spirit, that sign of love, perfects the single movement of God in himself. “The self-existence of the triune God,” writes Webster, “is his existence in the personal, internal activities of God” (2016: 20)
The being of God is abundant life. He has it in himself.
And his life means that God fittingly created us for life
By nature, God is life. He is life in himself by eternally begetting, being begotten, and spirating. The Father eternally begets the Son and spirates the Spirit, the Son eternally is begotten, and the Spirit eternally is spirated. This triune activity is God’s life. The invisible and immaterial life-giving nature of God means that he fittingly created the ages. He is who is life gives life.
That is who God is.
Small wonder then that he takes no delight death, even the death of the wicked: “As I live, declares the Lord GOD, I have no pleasure in the death of the wicked, but that the wicked turn from his way and live” (Ezek 33:11). As God lives, who has life in himself, he has no pleasure in the death of the wicked. He wants them to live. He wants them to have life—that is, the life of God.
John explains, “And this is the testimony, that God gave us eternal life, and this life is in his Son. Whoever has the Son has life; whoever does not have the Son of God does not have life.” (1 John 5:11–12). The life that God has in himself which is vibrant and full is granted to us, his creatures.
God’s aseity is why he gives life, salvation to the world
What we must conclude then is that “aseity is as it were the eternal impetus of the Son’s life-giving mission of salvation” (Webster 2016: 26 [he summarizes Augustine here]). God sent his Son into the word to save it by granting it eternal life which is the life that God has in himself. He did it simply because that is who God is. He is the fullness of life.
This is why, for example, the Father fittingly sent the Son to give life by the Spirit. The triune God’s life in itself which is paternity, filiation, and spiration comes to his creatures so that we might have abundant life.
So when we see Christ who is our life (Col 3:4), we will confess “For with you is the fountain of life” (Ps 36:9). And this fountain will satiate us forever because, as Jesus says, “Everyone who drinks of this water will be thirsty again, but whoever drinks of the water that I will give him will never be thirsty again. The water that I will give him will become in him a spring of water welling up to eternal life” (John 4:13–14).
Knowing that God is life means that you can be confident that God will give you life. That is who he is. Doubts cease when you know that God’s unchangeable nature is to be life. If he has promised life everlasting, there is no way he can lie. He is who he is. And that is the greatest blessing that we could ever hope for.