What you do not want done to yourself, do not do to others. Confucius
Every man is guilty of all the good he did not do. Voltaire
If it is not right do not do it; if it is not true do not say it. Marcus Aurelius
Dine with a friend but do not do business with him. Armenian Proverb
He who cannot work out his salvation by heart will not do it by book. French Proverb
Do not do evil - you will not be in eternal fear. Sumerian Proverb