The Platonists have understood that God must be a spiritual force, inherently living and infinite in nature, and this because all of the physical world is always changing and in flux, and hence cannot be the source of its own energy. It needs something unchanging and infinite beyond itself. This source (I suppose we should say "Source") must be simple, rational, living, and infinitely beautiful in its essential nature.
Not only did the Platonists get much of their doctrine of God correct, they are the best at understanding the nature and function of rational thought and logic. This is because they see that these things come from a source beyond the material world--a point which no other body of philosophy has acknowledged.