They came to John and said to him, “Rabbi, that man who was with you on the other side of the Jordan—the one you testified about—well, he is baptising, and everyone is going to him.”
RWP points out, “These disciples of John are clearly jealous of Jesus as a rival of John and they distinctly blame John for his endorsement of one who is already eclipsing him in popularity. The sight of the growing crowds with Jesus and the dwindling crowds with John stirred John’s followers to keenest jealousy. What a life-like picture of ministerial jealousy in all ages.” Although John does not give in to it, their worry on his behalf and for his ministry produced a temptation. Barclay points out that sometimes a friend’s sympathy can be a bad thing for us, because it can stir jealousy within us, which is something we are not supposed to have (Php 1:18).
Php 1:18 But what does it matter? The important thing is that in every way, whether from false motives or true, Christ is preached. And because of this I rejoice. Yes, and I will continue to rejoice,
Matthew Henry makes the good points that, “It was not indeed strange that all men came to him. As far as Christ is manifested he will be magnified; but why should John’s disciples grieve at this?”