Charles Ellicott Commentary Matthew 21:24

"And Jesus answered and said unto them, I also will ask you one question, which if ye tell me, I likewise will tell you by what authority I do these things." — Matthew 21:24 (ASV)

I also will ask you one thing — The question is met by another question. As One who taught as having authority, and not as the scribes (Matthew 7:29), He challenges their right to interrogate Him on the basis of precedent.

Had they exercised that right in the case of John the Baptist, and if so, with what result? If they had left his claim unquestioned, or if they had shrunk from confessing the result of their inquiry, they had virtually abdicated their office. In that case, they had no right, in logical consistency, to exercise it intermittently in the case of another teacher.