These therefore He chose for His disciples, whom also He named Apostles, humbly born without honour, without learning, that whatever they should do that was great, it was He that should be in them and should do it. He had among them one that was evil, whom He should use in the accomplishment of His Passion, and who should be an example to His Church of suffering evil men.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: City of God, book xviii, ch. 49