The Apostle says that there must be heresies (ibid.). But there must be — not that the heretics be what they are, but that the catholics endure what they are not. As the Lord said of Judas His betrayer, that it had been good for that man not to have been born (Matt. 26:24). For he says this to him, because your being born was an evil to him who betrayed, but a good to us, to whom salvation came through the betrayal.