Praying.

Sermon on the Mount Cont... Jesus said, "When you pray, don't be like the hypocrites. They like to stand in churches and street corners and pray so that everyone can see them. I tell you the truth. That will be their only reward. "But when you pray, go into your room, close the door and pray to your Father in secret, and your Father who sees in secret will reward you.

Our motive for praying is important to God. Some people pray to look religious and righteous. This is the wrong motive. We should never pray with pride in our hearts.

"When you pray, do not use meaningless repetition as the heathen do. They think they will be heard if they talk a lot.  Don't be like them, for your Father knows what you need before you ask Him."

Instead of motive, Jesus is now talking about our manner of praying. We do not need to repeat our prayers over and over as they do in some religions. God knows what we need. 

ill's Exposition of the Entire Bible

But when ye pray, use not vain repetitions,.... Saying the same things over and over again,

as the Heathens do, as the worshippers of Baal, from morning till noon, 1 Kings 18:26. This our Lord observes, to dissuade from such practices, because the Gentiles, who were odious to the Jews, used them, and the Jews were guilty of the same; had they not, there would not have been any need of such advice:

for they think they shall be heard for their much speaking; as did the Jews, who, under pretence of "long prayers", devoured widows' houses; and with whom it is an axiom, that "everyone , that multiplies prayer is heard" (h); and whoever prolongs his prayer, his prayer does not return empty; and he that is long in prayer, his days are prolonged (i): and, according to their canons, every day a man ought to pray eighteen prayers. Moreover, their prayer books abound in tautologies, and in expressing the same things in different words, and by a multiplicity of them.