“A fool is known by his Speech; and a wise man by Silence.”

Introductio ad prudentiam: Part II (1727)

Le silence est l'esprit des sots
Et l'une des vertus du sage.
Bernard de Bonnard, "Le Silence," http://books.google.com/books?id=9gAvAAAAMAAJ&pg=PR14&dq=%22Et+l%27une+des+vertus+du+sage%22+Bonnard&ei=iyzvR-bFOIa4zASV0PyoBQ#PPA244,M1 L'Almanach des Muses (1776)
Misattributed

Maxim 49
Sentences, The Moral Sayings of Publius Syrus, a Roman Slave

Jacula Prudentum (1651)

Touchstone, Act V, scene i
Source: As You Like It (1599–1600)

Touchstone, Act V, scene i
Misattributed

Vol. II, Ch. V Aphorisms and Extracts, p. 72.
Memoirs and Correspondence (1900)

Nahj al-Balagha