Will at Prydain posted this last week. St. Augustine is writing on Psalm 66, especially vs. 19 – 20
But truly God has listened;
he has attended to the voice of my prayer.
Blessed be God,
because he has not rejected my prayer
or removed his steadfast love from me!
(Psalm 66:19-20 ESV)
May these words encourage us to persevere in prayer,
DELAYS, NOT DENIALS.
So long as we are here, let us ask this of God, that He will not “remove from us our prayer, and His own mercy;” that is, that we may perseveringly pray, and He may perseveringly pity. For many grow languid in praying; and in the freshness of their conversion they pray fervently, afterwards languidly, afterwards coldly, afterwards negligently; they become, as it were, careless. The enemy is awake; you are sleeping. Our Lord Himself, in the Gospel, gave us the precept, “that men ought always to pray, and not to faint;” and He gives us an illustration from the unjust judge. Therefore let us not faint in prayer. Although He delays that which He is going to grant, He does not take it from us; since we may be confident of His promise, let us not faint in praying; and even this not fainting comes of His own bounty. Therefore he said, “Blessed be my God, who has not removed my prayer, and His mercy from me.” When you see that your prayer is not removed from you, be of good heart; for His mercy is not removed from you.
–St. Augustine on Psalm lxv. (our Ps. lxvi.)