John said to him, “Teacher, we saw someone casting out demons in your name, and we tried to stop him, because he was not following us.” But Jesus said, “Do not stop him; for no one who does a deed of power in my name will be able soon afterward to speak evil of me. Whoever is not against us is for us. For truly I tell you, whoever gives you a cup of water to drink because you bear the name of Christ will by no means lose the reward.
This is an interesting passage. It clearly highlights the difference of approach of Matthew’s gospel compared to Mark’s. In Matthew 12, in response to criticism Jesus receives for casting out demons he says, “Whoever is not with me is against me, and whoever does not gather with me scatters.”
Both passages have a similar context and content, though each has a different purpose. Mark’s gospel is seeking to include all who name Jesus in the work of the gospel. Matthew is seeking to show that those who oppose Jesus will themselves be opposed by God. Which approach is the best?
The first churches must have considered both to be of value to embrace both Mark and Matthews work. It’s not so much that one contradicts the other. Rather, between them, they create a tension in which those who wish to learn of Jesus can wrestle with the word and grow.