Since man is a social animal, one man naturally owes another whatever is necessary for the preservation of human society.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic society animal
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/18755/pg18755-images.html

Context

“for this virtue does not regard legal debt, which justice considers, but rather the moral debt, in so far as, out of equity, one man owes another a manifestation of the truth. Therefore truth is a part of justice, being annexed thereto as a secondary virtue to its principal. Reply Obj. 1: Since man is a social animal, one man naturally owes another whatever is necessary for the preservation of human society. Now it would be impossible for men to live together, unless they believed one another, as declaring the truth one to another. Hence the virtue of truth does, in a manner, regard something as being due.” source