Nevertheless, true fidelity towards a person may on occasion impose on us the duty to withdraw altogether from contact with him. In the case where he would constitute a threat to our fidelity to God, and when we on the other hand feel powerless to help him, our breaking off relations with him is still consistent with our true fidelity towards him: it is destined to promote his spiritual good as well as our own, and is therefore involved in our very love for him so far as love in a higher and ultimate sense implies, above all, responsibility.

Transformation in Christ
Dietrich von Hildebrand