Be not therefore like them: for your Father knows what things you have need of, before you ask him.
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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, what we have need of, wherefore must we pray? Not to instruct Him, but to prevail with Him; to be made intimate with Him, by continuance in supplication; to be humbled; to be reminded of your sins.