Catena Aurea on Matthew 6:7–8: Augustine of Hippo

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 violently broken off.

Herein themselves sufficiently shew, that this fervency of spirit, as it is not to be forced if it cannot last, so if it has lasted is not to be violently broken off. Let prayer then be without much speaking, but not without much entreaty, if this fervent spirit can be supported; for much speaking in prayer is to use in a necessary matter more words than necessary. But to entreat much, is to importune with enduring warmth the heart Him to whom our entreaty is made; for often is this business effected more by groans than words, by weeping more than speech.