I. "When thou prayest," the Lord says, "thou shalt not be as the hypocrites are: for they love to pray standing in the synagogues and in the corners of the streets, that they may be seen of men." Neither the synagogues nor the streets were the appointed places of prayer. But a custom had risen, since the days of Daniel the prophet, to pray seven times a day, at certain appointed hours; and when these hours came the Pharisee turned at once to his devotions. Very probably the iniquity of the Pharisee grew up in a very natural way, beginning with a scrupulous but honest observance of religious forms, and gradually sliding into a pretentious and hypocritical display as he found himself a growing object of respect and esteem among men. We also have need to be on our guard, and to watch and pray, and pray and watch, against this snare.
II. Our Lord enjoins that His people, when they pray, should enter into their closet, and shut to the door, and pray to the Father which seeth in secret. The true idea of prayer lies in the shutting of the door. You may make a closet for yourself out of the veriest crowd, provided you shut out the world from your thoughts and lift up your soul to God alone.
III. We are not to be like the heathen, who think they shall be heard for their much speaking. With them prayer was a kind of bodily and mechanical process, supposed to be efficacious just in proportion to the number of times they could repeat the same cry. Christ says that theirs is not true prayer such as becomes His children, and that we are not to do as they do, for our Father knoweth what things we have need of before we ask Him.
IV. When we pray, we should come believing in the unseen Father, and trusting in His gracious disposition. True prayer is just the cry of children to their Father, and it is the childlike feeling of trust in Him which gives to their prayer all its efficacy.
W. C. Smith, The Sermon on the Mount,p. 178.