Augustine of Hippo — on 2Cor 12:9 (AGAINST JULIAN 4.2.11)

“The more one easily conquers, the less one needs combat. But who would fight within himself if there were no opposition from self? And why is there opposition from self if nothing remains in us to be healed and cured? Therefore, the sole cause of our fighting is weakness in ourselves. Again, weakness cautions against pride. Truly, that strength and virtue by which one is not proud in this life where he could be proud is made perfect in weakness.”