Matthew 6:5-6 And when you pray, you must not be like the hypocrites. For they love to stand and pray in the synagogues and at the street corners, that they may be seen by others. Truly, I say to you, they have received their reward. 6 But when you pray, go into your room and shut the door and pray to your Father who is in secret. And your Father who sees in secret will reward you.

Prayer is such a prominent aspect of Christianity. Why do these verses seem to condemn the practice in public? Are all people who pray publicly hypocrites? What "reward" have the hypocrites already received? Why are there so many instances of public prayer elsewhere in the Bible? If public prayer is acceptable then what is the purpose of this passage? Does prayer even work?