Matthew 6:8

Be not therefore like them: for your Father knows what things you have need of, before you ask him.
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Augustine of Hippo

AD 430
As the hypocrites use to set themselves so as to be seen in their prayers, whose reward is to be acceptable to men; so the Ethnici (that is, the Gentiles)use to think that they shall be heard for their much speaking; therefore Headds, “When ye pray, do not ye use many words. "Cassian, Collat. ix. 36: We should indeed pray often, but in short form, lest if we be long in our prayers, the enemy that lies in wait for us, might suggest something for our thoughts. Epist., 130, 10: Yet to continue long in prayer is not, as some think, what is here meant, by “using many words.” For much speaking is one thing, and an enduring fervency another. For of the Lord Himself it is written, that He continued a whole night in prayer, and prayed at great length, setting an example to us. The brethren in Egypt are said to use frequent prayers, but those very short, and as it were hasty ejaculations, lest that fervency of spirit, which is most behoveful for us in prayer, should by longer continuance be viol...

Glossa Ordinaria

AD 1480
Ord.: What He condemns is many words in praying that come of want of faith; “as the Gentiles do.” For a multitude of words were needful for the Gentiles, seeing the daemons could not know for what they petitioned, until instructed by them; they think they shall be heard for their much speaking.

Gregory The Dialogist

AD 604
Mor. xxxiii. 23: True prayer consists rather in the bitter groans of repentance, than in the repetition of set forms of words.

Jerome

AD 420
Or this there starts up a heresy of certain Philosophers who taught the mistaken dogma that if God knows for what we shall pray, and, before we ask, knows what we need, our prayer is needlessly made toone who has such knowledge. To such we shortly reply, That in our prayers we donot instruct, but entreat; it is one thing to inform the ignorant, another to beg of the understanding: the first were to teach; the latter is to perform aservice of duty.

John Chrysostom

AD 407
And herewith He seems to me to command in this place, that neither should we make our prayers long; long, I mean, not in time, but in the number and length of the things mentioned. For perseverance indeed in the same requests is our duty: His word being, continuing instant in prayer. Romans 12:12 And He Himself too, by that example of the widow, who prevailed with the pitiless and cruel ruler, by the continuance of her intercession; Luke 18:1 and by that of the friend, who came late at night time, and roused the sleeper from his bed, Luke 11:5 not for his friendship's, but for his importunity's sake; what did He, but lay down a law, that all should continually make supplication unto Him? He does not however bid us compose a prayer of ten thousand clauses, and so come to Him and merely repeat it. For this He obscurely signified when He said, They think that they shall be heard for their much speaking. For He knows, says He, what things you have need of. And if He know, one may say...

John Chrysostom

AD 407
You do not then pray in order to teach God your wants, but to move Him, that you may become His friend by the importunity of your applications to Him, that you may be humbled, that you may be reminded of your sins.

Theophylact of Ochrid

AD 1107
It is not to inform God of anything that we make our petitions, but instead, that we may detach ourselves from the cares of life and receive benefit by conversing with God.

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

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