It looks as if the disciples and Jesus speak on two separate wavelengths. With the disciples this is the result of a lack of understanding (9:32); with Jesus it is the result of a continuous attempt at correcting the disciples and bringing them to conversion. They are thinking of a march of triumph: who will then lead the way? Jesus, however, speaks of a way of suffering: soon people will speak evil of him. This means that they will reject and curse him (see for κακολογέω as meaning “to curse” 7:10; Acts 19:9). Jesus’ statement does not in general mean that people who drive out demons in his name will not soon change their mind. The Saviour speaks clearly in connection with what is happening at the time: before long the people will speak evil of him (9:31), so they should be glad that there are still some in these weeks who will be friends in that hour. Disciples are worrying about their honour; Jesus sees a point of light on the way of dishonour. He who prepares himself for being totally left alone greets even a faraway friend. He who thinks that places of honour are being prepared stumbles even over a friend who stays a bit at a distance.1
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.