What was God doing before he created the world? Perhaps he was lonely. And being lonely, he needed to fill that empty hole in his heart. So he decided to create the world—that way he could have fellowship with others. Now that the world is here, God is not so lonely anymore. Because of us, he feels fulfilled and whole.
This answer is not uncommon. It can be heard in many churches today by well-meaning Christians. Please brace yourself, because I have something shocking to say: God does not need you. He doesn’t need you, he doesn’t need me, and he doesn’t need anyone or anything in this world. In fact, he doesn’t need the world at all. Period.
God is not a needy God. It’s not as if he was bored, twiddling his thumbs, desperately lonely prior to creating the world. God is not dependent on the world for his existence, nor is he dependent on the world for his happiness and self-fulfillment. Instead, he possesses life in and of himself. More precisely, he is the fullness of life in and of himself.
What is aseity? Life in and of himself
What we are describing is the attribute of aseity—a se being Latin, meaning “from himself.” As I argue in None Greater: The Undomesticated Attributes of God, to affirm God’s aseity is to say, first and foremost, that he is life in and of himself, and on that basis he must be self-existent and self-sufficient. It is because God is life in and of himself that there can be no sense in which he is caused by another.
There is, most fundamentally, a difference in nature between the Creator and the creature, the former having life in and of himself, the latter deriving life from the one who is life. We are born into this world totally dependent, finite in every way. Our existence is derived from our mother and father. If we are to continue living, the God of the universe must sustain us. We are dependent on not only our earthly father but our heavenly Father too. Our nature, our very existence, is contingent in every way.
Not so with God. His nature is not at all like our nature. He is incommensurable, incapable of being measured by the same standards of our human existence. Unlike everything in this world, his existence is not grounded in, derived from, or contingent on something or someone else. No one brought him into being, nor is he dependent on something or someone else to continue being. He is underived from and unconditioned by that which is finite, contingent, limited, and changeable. That much is evident in how he created the world. He did not depend upon some preexisting matter to create the universe, but he created ex nihilo, out of nothing.
Furthermore, only one who has no beginning or cause to his own existence can bring the world into existence out of nothing (an unmoved mover). Uncaused, his existence is grounded in himself alone. That means not that he created himself or caused himself to be but that he alone, as Anselm says, “has of himself all that he has, while other things have nothing of themselves. And other things, having nothing of themselves, have their only reality from him.”
That phrase “has of himself all that he has” handsomely summarizes aseity. The same cannot be said of objects in the created order. Placed next to God, observes Augustine, “they are deficient in beauty and goodness and being.” But there is no such deficiency in God’s being. Aseity defines God as a perfect being.
Editor’s Note: This post originally appeared at the blog for Credo Magazine and is used with permission.
 Anselm, On the Fall of the Devil 1.
 Augustine, Confessions 11.4.