From Big Truths for Young Hearts by Bruce Ware:
God is so amazingly great, so perfectly strong, and so completely different from everyone and everything else that he is able to live fully as God without any help from anyone or anything. God doesn’t need air to breathe or food to eat or water to drink. He doesn’t need help with the work that he decides to do. Rather, God always has, within his own life, everything he needs for being who he is as God and for doing all that he chooses to do. He doesn’t need anything at all in the whole world, even though everything in the world needs God. So, God is God—completely and perfectly—without anything in the world helping God to be God.
It is hard to think of God this way, but it is important to learn that this is who God really is. Everything else, and everyone else, in all of the world has to depend on certain things or on certain people. If we listed all of the things that we need—things that we don’t have in our own lives but must receive in order to live and to do what we want to do—we would be amazed at how long the list would be. But God has no such list! Nothing in the entire world can add to God or can give to God something that he lacks. He has everything—yes everything!—that really is good, and he has all of this within his own life as God. There is not one single good quality that is not contained within God’s own life as God. Anything that you can think of that really is good—all truth, all wisdom, all power, all kindness, all love, all righteousness, and every other good thing—is in the very life of God, and it has always been this way. It is simply impossible for God to lack any good thing, because by his very life and being he is the one who has everything that truly and really is good. So, God is God, fully and completely, apart from us and apart from the world he has made.