Jesus already told us not to practice our righteousness before others to be noticed by them. But sometimes that can't be helped, right? If you bring a meal to someone's home they will know that you did it. If you teach a children's Sunday school class you can't hide the fact from the rest of the church. If you play an instrument on the worship team, you're right up front where everyone can see you. So Jesus mentions three things in this chapter that you can do in secret. One is to give money to the poor. Another is to pray. Another is to fast. Here he talks about giving.
Jesus sure has a wicked sense of humor. He says, "People, please. Don't bring your trumpets with you to the synagogue and blow them as you dangle your money over the coffer saying, 'Hear ye, hear ye! A great deed of charity is about to be done before your eyes today!" then drop your bundle of cash in with an impressive clunk! (Round of applause. Deed-doer bows and waves.) Sorry, no reward in heaven for pulling that little stunt.
He says the problem with seeking attention for a good deed is that you already have your reward when people applaud you. If you give to please people, you will get human praise for your efforts, but if you give to please God, you will receive your praise from him. And God knows that your true motives are to seek his praise alone when your giving is done secretly--so secretly that your left hand doesn't know what your right hand is doing.
Since it's impossible for the left hand to be ignorant of what the right hand is doing, I'd have to assume that Jesus is using hyperbole here. He's saying the extent of your secrecy should be to keep the secret of your giving even from yourself. Whenever I read this, the only application I could come up with is to try to give with a certain forgetfulness. You give and move on. Don't dwell on it. Don't keep track of it. Don't pat yourself on the back over it. (But of course now that I'm writing this blog post, I am dwelling on it and remembering times I've given that I've tried to forget. And so by talking about the application of this passage, I guess I'm ruining my ability to effectively apply it. That is, if my application is even valid in the first place. Anyhow.)
What really fascinates me about this passage is that God feels a need to "repay" you when you practice your piety in secret. He knows you have put yourself in a position where you will get no recognition, no brownie points, no handshakes or backslaps or that nomination to serve on the elder board because of your efforts. In fact your "unflashiness" might even cause you to be ignored or misunderstood. As much as we talk about valuing humility in the church, we don't actually gravitate toward the quiet, unimpressive, humble types. We reward the outgoing, well-spoken, flashy people with all the best leadership positions in the church. So God compensates the ones who are overlooked precisely because they have forsaken the praise of others to please their heavenly Father. It could be that the guy who folds bulletins in the back room will receive a greater reward than the worship leader who makes a display of her singing talents up front. Or the person who leaves the cup of water inside the pulpit every Sunday will receive a greater reward than the preacher who sips that water while preaching his fiery sermon. Until the day comes when all secrets are revealed, you just can't tell how things will pan out.