Wherefore the perfection of human good, which is called happiness, cannot be caused by human knowledge: but rather human knowledge of another's happiness proceeds from, and, in a fashion, is caused by, human happiness itself, inchoate or perfect. Consequently man's happiness cannot consist in fame or glory. On the other hand, man's good depends on God's knowledge as its cause.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic perfection happiness
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/17897/pg17897-images.html

Context

“says. Now the thing known is related to human knowledge otherwise than to God's knowledge: for human knowledge is caused by the things known, whereas God's knowledge is the cause of the things known. Wherefore the perfection of human good, which is called happiness, cannot be caused by human knowledge: but rather human knowledge of another's happiness proceeds from, and, in a fashion, is caused by, human happiness itself, inchoate or perfect. Consequently man's happiness cannot consist in fame or glory. On the other hand, man's good depends on God's knowledge as its cause. And therefore man's beatitude depends, as on its cause, on the glory which man has with God; according to Ps. 90:15, 16: "I will deliver him, and I will glorify him; I will fill him with length of days, and I will show him my salvation."” source