"IN GOD to live is to understand. In God intellect, the thing understood, and the act of understanding, are one and the same. Hence whatever is in God as understood is the very living or life of God. Now, wherefore, since all things that have been made by God are in Him as things understood, it follows that all things in Him are the divine life itself...
"Creatures are said to be in God in a twofold sense. In one way, so far are they are held together and preserved by the divine power; even as we say that things that are in our power are in us. And creatures are thus said to be in God, even as they exist in their own natures. In this sense we must understand the words of the Apostle when he says, "In Him we live, move, and be"; since our being, living, and moving are themselves caused by God. In another sense things are said to be in God, as in Him who knows them, in which sense they are in God through their proper ideas, which in God are not distinct from the divine essence. Hence things as they are in God are the divine essence. And since the divine essence is life and not movement, it follows that things existing in God in this manner are not movement, but life."
~St. Thomas Aquinas: Summa Theologica, I, Q. 18. Art. 4.
