Augustine of Hippo — as excerpted in the Catena Aurea on Luke 18:1-8

“(ut sup.) If then with the most unjust judge, the perseverance of the suppliant at length prevailed even to the fulfilment of her desire, how much more confident ought they to feel who cease not to pray to God, the Fountain of justice and mercy? And so it follows. And the Lord said, Hear what, &c.”