6 Do you, therefore, holy scions of our one Catholic mother, beware with all the watchfulness of which you are capable, in due submission to the Lord, of the example of crime and error such as this. With however great light of learning and of reputation he may shine, however much he may boast himself to be a precious stone, who endeavors to lead you after him, remember always that that brave woman who alone is lovely only to her husband, whom holy Scripture portrays to us in the last chapter of the Book of Proverbs, is more precious than any precious stones.
Let no one say, I will follow such an one, for it was even he that made me a Christian; or, I will follow such an one, for it was even he that baptized me. For "neither is he that plants anything, neither he that waters, but God that gives the increase." And "God is love; and he that dwells in love, dwells in God, and God in him." No one also that preaches the name of Christ, and handles or administers the sacrament of Christ, is to be followed in opposition to the unity of Christ.
"Let every man prove his own work; and then shall he have rejoicing in himself alone, and not in another. For every man shall bear his own burden," — the burden, that is, of rendering an account; for "every one of shall give an account of himself. Let us not therefore judge one another any more." For, so far as relates to the burdens of mutual love, "bear ye one another's burdens, and so fulfill the law of Christ. For if a man think himself to be something, when he is nothing, he deceives himself." Let us therefore "forbear one another in love, endeavoring to keep the unity of the Spirit in the bond of peace;" for no one who gathers outside that peace is gathering with Christ; but "he that gathering not with Him scatters abroad."
Source: Answer to Letters of Petilian, Bishop of Cirta (New Advent)