Today our Lord teaches us an important lesson on tolerance. The Apostles have seen someone casting out demons using Jesus’ name and tried to stop them but Jesus preaches tolerance.
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.” 39 But Jesus said, “Do not stop him, for no one who does a mighty work in my name will be able soon afterward to speak evil of me. 40 For the one who is not against us is for us. 41 For truly, I say to you, whoever gives you a cup of water to drink because you belong to Christ will by no means lose his reward.
There are a few things to notice about this. First, notice that it does not say that this person is a disciple, all it says is that they are using Jesus’ name. There is no evidence here that there is more than one group of legitimate disciples.
Second, notice what Jesus implies is that when someone uses his name and sees the results they will not after speak evil of him. Specifically, Jesus says that someone who, “does a mighty work” will not speak evil of Jesus. Jesus is implying that the success in using his name will produce good will towards him. That is confirmed in the next sentence when Jesus says “who is NOT AGAINST US is for us”. This is a specific criteria, one cannot under any circumstances, be against Jesus AND his Apostles (us), which is the Church, and still be for Jesus.
Third this passage must be read in context of Jesus other teachings. Note that it is John who is raising this point with Jesus. It is John, who will later convey this teaching of Jesus in his Gospel,
22 If I had not come and spoken to them, they would not have been guilty of sin, but now they have no excuse for their sin.
In other words, people are not responsible for what they don’t know. However, after Jesus has spoken to them (presumably through the Holy Spirit) they are responsible. This person who is using Jesus’ name to cast out demons seems to be unaware that he might be doing something wrong. However, after he is spoken to, he would be responsible for his actions.
How then should the Apostles have handled this issue? We read about a similar circumstance in the book of Acts when Apollos was preaching the Gospel without having been initiated.
Now a Jew named Apollos, a native of Alexandria, came to Ephesus. He was an eloquent man, competent in the Scriptures. 25 He had been instructed in the way of the Lord. And being fervent in spirit, he spoke and taught accurately the things concerning Jesus, though he knew only the baptism of John. 26 He began to speak boldly in the synagogue, but when Priscilla and Aquila heard him, they took him aside and explained to him the way of God more accurately.
We are reminded here that it was not impossible for Apollos to teach about Jesus before he was part of the Church. However, once he was joined to the Church and received the fullness of the Holy Spirit he met with greater success. “… he greatly helped those who through grace had believed, 28 for he powerfully refuted the Jews in public, showing by the Scriptures that the Christ was Jesus.”