79. For it is needful to separate one who has grievously fallen, lest a little leaven corrupt the whole lump. And the old leaven must be purged out, or the old man in each person; that is, the outward man and his deeds, he who among the people has grown old in sin and hardened in vices. And well did he say purged, not cast forth, for what is purged is not considered wholly valueless, for to this end is it purged, that what is of value be separated from the worthless, but that which is cast forth is considered to have in itself nothing of value.