The true Christian should not resign himself to the inevitable: he should trust in the impertinence of a repeated prayer.

— Nicolás Gómez Dávila (1913-1994)

Christ gave us the parable of the importunate widow:

And he spake a parable unto them to this end, that men ought always to pray, and not to faint; saying,

There was in a city a judge, which feared not God, neither regarded man: and there was a widow in that city; and she came unto him, saying, Avenge me of mine adversary. And he would not for a while: but afterward he said within himself, Though I fear not God, nor regard man; yet because this widow troubleth me, I will avenge her, lest by her continual coming she weary me.

And the Lord said,

Hear what the unjust judge saith. And shall not God avenge his own elect, which cry day and night unto him, though he bear long with them? (Luke 18:1-7)

We worry (with good reason) about “vain repetitions”, but Christ reminds us that not all repetitions are in vain; some, in fact, are essential.