Luke 9:46-50

Luke 9:46 An argument started among them as to which of them might be the greatest. 47 But Jesus, knowing what they were thinking in their heart, took a child and stood him by His side, 48 and said to them, “Whoever receives this child in My name receives Me, and whoever receives Me receives Him who sent Me; for the one who is least among all of you, this is the one who is great.” 49 John answered and said, “Master, we saw someone casting out demons in Your name; and we tried to prevent him because he does not follow along with us.” 50 But Jesus said to him, “Do not hinder him; for he who is not against you is for you.” (NASB)

I don't hear many people talking about these verses for some reason. It isn't the most comfortable of all verses I will admit, I can think of a lot of people who I wouldn't want to align myself with by saying that we ultimately believe the same thing, in fact most times I might try to distance myself from them by highlighting our differences. But that is not what Jesus is telling us to do here. John basically comes to Jesus and says that because this man is not part of their group he shouldn't be able to cast out the demons, John latter would change the criteria by which he would judge someones ministry from what group they are in to, simply, whether or not they would preach Christ 1 John 4:1-4.

Jesus' response to John is to make it clear that there is no in between, if someone is teaching the name of Christ that is what is important, either someone is helping you or not. Later in Luke 11:23 Jesus puts it a different was saying "He who is not with Me is against Me; and he who does not gather with Me, scatters." Jesus makes it clear that the way in which we are to judge mans ministry is by who's name he does it by. It is either Christ or by the world.