Here are a few of my favorite quotes from Treasury of Proverbs and Epigrams.
To do well is to choose wisely.
The conscience of well-doing is an ample reward.
Do good by stealth, and blush to find it fame.
Do good and care not to whom.
He/she who fasteth and doeth no good, saveth his/her bread, but loseth his/her soul.
They do much that do a little well.