"The quintessence of wickedness is foolishness." ~~ The Chofetz Chaim
"The man who does not lend money on interest, either to Jew or Gentile, walks with honor." ~~ Talmud, Makkoth 24a
"Who pities not mankind, be it known that he is not the seed of our Father Abraham! " ~~ Talmud, Beitza
"Sinning in Eretz Israel is worse than elsewhere…It is like rebellion right within the king’s own palace." ~~ Meir of Rothenburg
"Three things drain a man’s health: worry, travel and sin." ~~ Talmud, Gittin 70a
"The punishment of vain hatred is so harsh that it destroyed Jerusalem and the Temple. " ~~ Beth Hamidrash
"What you don’t see with your eyes, don’t invent with your mouth. " ~~ Traditional Proverb
"Exile atones for everything. Exile expiates sins." ~~ Talmud, Sanhedrin
"Quarrel not with a man without reason, when he has done you no harm! " ~~ Proverbs (Mishle) 3:30
"Cast not a stone into the well whence you drank! [Bite not the hand that feeds you!] " ~~ Numbers (Bamidbar) R.
"There is no one who never stumbled." ~~ Samuel Ha-Nagid
"If you cling to wisdom, you cannot cling to [impure] desires." ~~ The Mezeritzer Rabbi