But when you give to the needy, do not let your left hand know what your right hand is doing,
3. Let not thy left hand know By this expression he means, that we ought to be satisfied with having God for our only witness, and to be so earnestly desirous to obey him, that we shall not be carried away by any vanity. It frequently happens, that men sacrifice to themselves rather than to God.
As we must do better than the scribes and Pharisees in avoiding heart-sins, heart-adultery, and heart-murder, so likewise in maintaining and keeping up heart-religion, doing what we do from an inward, vital principle, that we may be approved of God, not that we may be applauded of men; that is, we must watch against hypocrisy, which was the leaven of the Pharisees, as well as against their doctrine, Luk 12:1.
Commenting on Matthew 6:1-4
But when thou dost alms,.... Do it so privately, and with so much secrecy, that, if it was possible, thou mightest not know it thyself, much less make it known to others: let not thy left hand know what thy right hand doth; acquaint not thy nearest and dearest friend with it; let not one that sits at thy left hand know what thou art...