Jesus’ teaching here is related to the former concerning the disciples’ pride. The Twelve were more exclusive than Jesus. Jesus’ disciples wanted to stop a man who they believed was practicing faith without Jesus’ official license and authority. He was not “one of them.” They were greater, and he was lesser, was the thought that drove the disciples to want to stop him. Happily, they asked Jesus before they stopped him.
Jesus told his disciples to not stop the man who was driving out demons in Jesus’ name. Then he gave them a brief lesson. “Whoever is not against you is for you.” Jesus contrasted the opposition the religious leaders were giving them because they were not taught by one of them to their request to stop the man acting in Jesus’ name because he was not one of them. The disciples’ hearts were fermenting the yeast of the religious leaders.
Institutionalized religious education has its benefits. However, it has just as many inherited problems and even hindrances to the spread of the gospel. Silo-authority mentality and niche-group practices can be more harmful to a believer than the threat of world mentality. Neither Jesus, John the Baptist, many of the prophets, and even the Twelve went to the equivalent of a seminary school in their time.