Matthew 6:5

And when you pray, you shall 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. Verily I say unto you, They have their reward.
Read Chapter 6

Augustine of Hippo

AD 430
And here also it is not the being seen of men that is wrong, but doing these things for the purpose of being seen of men; and it is superfluous to make the same remark so often, since there is just one rule to be kept, from which we learn that what we should dread and avoid is not that men know these things, but that they be done with this intent, that the fruit of pleasing men should be sought after in them. Our Lord Himself, too, preserves the same words, when He adds similarly, Verily I say unto you, They have received their reward; hereby showing that He forbids this—the striving after that reward in which fools delight when they are praised by men.

Cornelius a Lapide

AD 1637
And when ye pray, &c. Foolish and imprudent was this vanity and ostentation of the Scribes by which they affected the public streets, where was a greater crowd of people, that they might stand before them, and exhibit their prayers and devotion, when they ought rather to have sought for a secret place for prayer, in which they might collect their thoughts, and converse with God alone without distraction. What therefore is commonly said of three places unfit for study, that it is useless at a window, in the street, by the hearth, because of the various distractions which occur at those places, may be even more truly said of prayer. Prayer is useless at a window, in the street, by the hearth. Stand praying. From this and other passages Jansen is of opinion that the Jews stood, not knelt, to pray. But I say that the Priests and Levites sacrificed and sang Psalm to God standing, and the people who were present also stood, because if they had knelt they would have been unable to witness th...

George Leo Haydock

AD 1849
Hypocrisy is forbidden in all these three good works of justice, but not the doing of them openly for the glory of God, the edification of our neighbour, and our own salvation. Let your light so shine before men, i.e. let your work be so done in public, that the intention remain in secret. (St. Gregory)

John Chrysostom

AD 407
While pretending to pray to God, the hypocrites are looking around for human praise. The elaborate garb they wear is laughable, and hardly that of a sincere supplicant. One who is earnestly offering a supplication looks exclusively to the One who has the power to grant the request and lets all other claims recede. But if you leave behind the one you are petitioning and immediately go wandering about looking everywhere for others’ approval, you will depart with empty hands. The Gospel of Matthew, Homily

John Chrysostom

AD 407
These too again He calls hypocrites, and very fitly; for while they are feigning to pray to God, they are looking round after men; wearing the garb not of suppliants, but of ridiculous persons. For he, who is to do a suppliant's office, letting go all other, looks to him alone, who has power to grant his request. But if you leave this one, and go about wandering and casting around your eyes everywhere, you will depart with empty hands. For this was your own will. Wherefore He said not, such shall not receive a reward, but, they have it out: that is, they shall indeed receive one, but from those of whom they themselves desire to have it. For God wills not this: He rather for His part was willing to bestow on men the recompence that comes from Himself; but they seeking that which is from men, can be no longer justly entitled to receive from Him, for whom they have done nothing. But mark, I pray you, the lovingkindness of God, in that He promises to bestow on us a reward, even for thos...

John Chrysostom

AD 407
Your inner will cannot be hid. This is why Jesus did not say, “They shall not receive a reward” but “They have received their reward”—already! Their reward comes from those from whom they themselves most desire to get it. God does not desire this. For God preferred to bestow upon humanity the grace that comes only from himself. Those who seek their reward from people cannot receive another reward from the One for whom they have sought nothing. The Gospel of Matthew, Homily

John Chrysostom

AD 407
When you pray, it is as if you were entering into a palace—not a palace on earth, but far more awesome, a palace in heaven. When you enter there, you do so with complete attentiveness and fitting respect. For in the houses of kings all turmoil is set aside, and silence reigns. Yet here you are being joined by choirs of angels. You are in communion with archangels and singing with the seraphim, who sing with great awe their spiritual hymns and sacred songs to God, the Lord of all. So when you are praying, mingle with these voices, patterning yourself according to their mystical order. It is not to human beings that you are praying but to God, who is present everywhere, who hears even before you speak and who knows already the secrets of the heart. If you pray to this One, you shall receive a great reward. “For your Father who sees in secret shall reward you openly.” He did not merely say he would give it to you but reward you, as if he himself had made a pledge to you and so honored you...

Theophylact of Ochrid

AD 1107
. He also calls those men hypocrites who pretend they are looking to God when in fact they are looking to men; and from men they have received the only reward they will receive.

Knowing this first, that no prophecy of the scripture is of any private interpretation - 2 Peter 1:20

App Store LogoPlay Store Logo