S. Maximus, Vol. II. 114.

Being is in God. God is divine being, eternal and without beginning, incorporeal and illimitable, and the cause of what exists. Being is that which wholly subsists. Nature is the truth of things, or the inner reality of them. According to others, it is the production of what has come to existence; and according to others, again, it is the providence of God, causing the being, and the manner of being, in the things which are produced.