As with giving, the reward received is the praise of men. If you pray in order to win the attention of people and make them think that you are particularly pious, this will be the result of your prayers. Your prayers will not earn any favours with God, and they are the mark of someone who does not know God as Father.
5 “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.