Augustine of Hippo — on Rom 8:26 (LETTER 130)

“We must not deduce from this that either the apostle or those to whom he spoke were unacquainted with the Lord's Prayer. We think that the reason Paul says that we do not know how we should pray … was because temporal trials and troubles are often useful for curing the swelling of pride or for proving and testing our patience, and by this proving and testing winning for it a more glorious and precious reward; or for chastising and wiping out certain sins, while we, ignorant of these benefits, wish to be delivered from all trouble.”