Pseudo-Chrysostom
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.
(Vict. Ant. e Cat. in Marc.) In conformity to this, He shews that he is not to be forbidden, adding immediately after, For there is no man which shall do a miracle in my name, that can lightly speak evil of me. He says lightly, to meet the case of those who fell into heresy, such as were Simon and Menander, and Cerinthusk; not that they did miracles in the name of Christ, but by their deceptions had the appearance of doing them. But these others, though they do not follow us, cannot however set themselves to say any thing against us, because they honour My name by working miracles.