Aseity is the property that describes a being’s self-causation. In theology, to speak of divine aseity is to say that God exists in and of Himself. He is not derived from or dependent upon anything else. He is fully Himself in Himself and of Himself. He is a se.
It might seem that aseity is opposed to dependence or derivation of any sort. If a being possesses the quality of aseity, that being cannot derive his existence from any other.
But the New Testament presents the strange spectacle of derived aseity. In John 5, Jesus says that the Father “has life in Himself” and even so “He gave to the Son also to have life in Himself” (v. 26). This is not simply a gift of life; it is a gift of life a se and in se: “He gave to the Son to have life in Himself” (Gr. en heauto).
So in the Triune life, there is the underived, ungifted aseity of the Father, and also the derived, bestowed aseity of the Son. There is aseity given, and aseity received, paternal aseity and filial aseity. This is not an ontological subordination, because the Father is Father only insofar as He has a Son, which is to say, only insofar as He gives the gift of aseity to the Son. The Father’s fatherhood depends on His giving this gift. And of course the Son is Son only as aseity received from the Father.This pattern of gift and reception is the eternal root of the possibility of creation. It’s another way to state the perennial insight that the begetting of the Son is the uncreated ground for creation.
Each creature has its own integrity and individuality. Creatures are entirely dependent upon God’s gift of life, and yet creatures are not simply extensions of divine substance. We are truly distinct and a cause of our own actions. God makes beings who have an integrity in and of themselves, who possess a created reflex of God’s own aseity, and He is capable of doing this because the Father has eternally begotten the Son and bestowed aseity on Him. The given-and-received aseity within the Triune life is the foundation for the image of aseity that we see in creatures.