John Wesley on Mark 9:39

Jesus said - Christ here gives us a lovely example of candour and moderation. He was willing to put the best construction on doubtful cases, and to treat as friends those who were not avowed enemies. Perhaps in this instance it was a means of conquering the remainder of prejudice, and perfecting what was wanting in the faith and obedience of these persons. Forbid him not - Neither directly nor indirectly discourage or hinder any man who brings sinners from the power of Satan to God, because he followeth not us, in opinions, modes of worship, or any thing else which does not affect the essence of religion.