Jesus uses the image of a reed, common in the Jordan Valley, which is easily swayed by the wind. Commentators explain this is a metaphor for a fickle, inconstant person. By asking this rhetorical question, Jesus powerfully affirms that John the Baptist was the exact opposite: a man of unshakeable conviction. His recent inquiry was not a sign of a failing faith, but a moment Jesus used to confirm John's steadfast character.