"Be careful not to give to charity in public in order to attract attention. If you do, your Father in heaven will not reward you. So when you give to the poor, don't announce it with trumpets. This is what people do in order to be praised by men. Truly, that will be their only reward."
" But when you give to the needy, don't let your right hand know what your left hand is doing. Give your money privately. Your Father sees what you do in private. He will reward you." Matthew 6:1-4
Jesus is speaking of our motives for giving in this passage. Do we give so people will praise us and think we are wonderful people? Or do we give because our hearts are filled with compassion?
I remember once being in church and a lady who was in charge of money given to missions wanted people to stand up and tell everyone what they gave. No one did, because I think they felt it might be wrong to tell people. Not letting your right hand know what your left hand is doing means to give the money and then forget about it.