The essence of prayer

Some people, wanted to be seen as "holy", and public prayer was one way to get attention.  Jesus saw through their self-righteous acts, however, and taught that the essence of prayer is not public style but private communication with God.  There is a place for public prayer,
but to pray only where others will notice you indicates that your real audience is not God.  

Matthew 6:5 talked about how Jesus teaches about prayer "And when you pray, do not be like the hypocrites, for they love to pray standing in the synagogues and on the street corners to be seen by men.  I tell you the truth, they have received their reward in full.  But when you pray, go into your room, close the door and pray to your Father, who is unseen.  Then your Father, who sees what is done in secret, will reward you.  and when you pray, do not keep on babbling like pagans, for they think they will be heard because of their many words.  Do not be like them, for your Father knows what you need before you ask Him".

SOURCE: Life Application Study Bible