Further, if a man may not hope in another man, it ought not to be reckoned a sin in a man, that one should not be able to hope in him.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic sin hope
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

“Now we are helped to obtain eternal happiness by the patronage of the saints, for Gregory says (Dial. i, 8) that "predestination is furthered by the saints' prayers." Therefore one may hope in man. Obj. 2: Further, if a man may not hope in another man, it ought not to be reckoned a sin in a man, that one should not be able to hope in him. Yet this is reckoned a vice in some, as appears from Jer. 9:4: "Let every man take heed of his neighbor, and let him not trust in any brother of his." Therefore it is lawful to trust in a man. Obj. 3:” source