John Chrysostom
He inquires of them, asking, 'Where did the baptism of John come from, was it from heaven or from men?' You may wonder how this pertains to the matter. It is highly significant. Had they responded 'From heaven,' He would have retorted, 'Then why did you not have faith in it?' For had they truly believed, they would not have posed the question, as John proclaimed of Him, 'He was not worthy to loosen the strap of His sandal' (Luke 3:16); and once more, 'Behold the Lamb of God, who takes away the sin of the world' (John 1:29); and also, 'This is the Son of God' (John 1:34); and again, 'He who comes from heaven is above all' (John 3:31); and yet again, 'His winnowing fork is in His hand, and He will clear His threshing floor' (Matthew 3:12). Thus, if the Jews had accepted John’s testimony, there would be no confusion regarding the authority by which Christ operates.
See Matthew 21:23.