John Mark
Mark 9:38ESV·traditional attribution

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.”

John Calvin Reformed @genevareformer

Mark 9:38. Master, we saw one. Hence it is evident that the name of Christ was at that time so celebrated, that persons who were not of the number of his intimate disciples used that name, or perhaps even abused it, for I will not venture to avouch any thing on this point as certain.

Matthew Henry Presbyterian @wholebiblehenry

Here, I. Christ foretels his own approaching sufferings. He passed through Galilee with more expedition than usual, and would not that any man should know of it (Mar 9:30); because he had done many mighty and good works among them in vain, they shall not be invited to see them and have the benefit of them, as they have been.

Commenting on Mark 9:30-40

John Gill Reformed Baptist @doctorgill

And John answered him, saying,.... Taking notice of what Christ just now said, and observing how well pleasing it was to him, to receive in a meek and humble manner, the least believer in his name; and reflecting upon an action, in which he and some of his fellow disciples were concerned, and which he perceived was not so agreeable to this rule of Christ...