Gregory the Great
Catena Aurea · Markusevangelium 9
And John answered him, saying, Master, we saw one casting out devils in thy name, and he followeth not us: and we forbad him, because he followeth not us. But Jesus said, Forbid him not: for there is no man which shall do a miracle in my name, that can lightly speak evil of me. For he that is not against us is on our part. For whosoever shall give you a cup of water to drink in my name, because ye belong to Christ, verily I say unto you, he shall not lose his reward. And whosoever shall offend one of these little ones that believe in me, it is better for him that a millstone were hanged about his neck, and he were cast into the sea.
(de cura past. p. i. c. 2) Mystically by a millstone is expressed the tedious round and toil of a secular life, and by the depths of the sea, the worst damnation is pointed out. He who therefore, afterhaving been brought to a profession of sanctity, destroys others, either by word or example, it had been indeed better for him that his worldly deeds should render him liable to death, under a secular garb, than that his holy office should hold him out as an example for others in his faults, because doubtless if he had fallen alone, his pain in hell would have been of a more endurable kind.