for a man is not the same as his humanity. Therefore God is not the same as His Godhead.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic humanity God
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/17611/pg17611-images.html

Context

“Therefore it seems that God is not the same as His essence or nature. Obj. 2: Further, the effect is assimilated to its cause; for every agent produces its like. But in created things the suppositum is not identical with its nature; for a man is not the same as his humanity. Therefore God is not the same as His Godhead. On the contrary, It is said of God that He is life itself, and not only that He is a living thing: "I am the way, the truth, and the life" (John 14:6) . Now the relation between Godhead and God is the same as the relation between life and a living thing.” source