Sri Aurobindo

 God is the one stable and eternal Reality. He is One because

there is nothing else, since all existence and non-existence are He. He is stable or unmoving, because motion implies change in Space and change in Time, and He, being beyond Time and Space, is immutable. He possesses eternally in Himself all that is, has been or ever can be, and He therefore does not increase or diminish. He is beyond causality and relativity and therefore there is no change of relations in His being