For the greatness of God is nothing but the perfection of His nature.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic greatness perfection
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, since in the Father there are three notions, while in the Son there are only two, the Son is evidently not equal to the Father. On the contrary, It is said (Phil. 2:6) : "He thought it not robbery to be equal with God." I answer that, The Son is necessarily equal to the Father in greatness. For the greatness of God is nothing but the perfection of His nature. Now it belongs to the very nature of paternity and filiation that the Son by generation should attain to the possession of the perfection of the nature which is in the Father, in the same way as it is in the Father Himself.” source