And they asked him, and said unto him,.... They put a question, by saying to him,
why baptizest thou then, if thou be not that Christ, nor Elias, neither that prophet? since he denied that he was the Messiah, or Elias that was to come before the Messiah, according to the expectation of the Jews, or that prophet, or a prophet, they demand by what authority he introduced a new rite and ordinance among them, which they had never been used to; for though there were divers washings or baptisms among them, enjoined by the law of Moses in certain cases, and others which obtained by tradition, as the immersion of themselves after they had been at market, and of cups, pots, brazen vessels, and tables, yet nothing of this kind that John administered: and as for the baptism of proselytes, it seems to be of a later date than this, and had no manner of likeness to it. The ordinance John administered was such, as they apprehended that no one ought to practise, unless he was the Messiah, or his forerunner, or some eminent prophet; they insist upon it therefore, that since he denied he was either of these, that he would show his credentials, and what commission he had from God to baptize; or they suggest he was liable to be called to an account by their sanhedrim, and be condemned as a false prophet, or an innovator in religious affairs. From hence it appears, that the Jews expected that baptism would be administered in the times of the Messiah, and his forerunner; but from whence they had this notion, it is not easy to say, whether from Zechariah 13:1 as Grotius, or from Ezekiel 36:25 as Lightfoot; nor do they speak contemptibly of it, but rather consider it as a very solemn affair, to be performed only by great personages: and this may teach modern ones to think and speak more respectfully of this ordinance than they do, who have given themselves great liberties, and have treated it with much contempt and virulence; calling it by the names of uncleanness, abomination, filthy water, and a devoting of persons to Satan (z): likewise, it is clear from hence, that they expected that this ordinance would be first administered by some person of very great note, either some very famous prophet, as Elias, whom they looked for before the coming of the Messiah, or else the Messiah himself, and not by a common teacher, or any ordinary person; wherefore this rite, as performed by John, could have no likeness with any thing that was in common use among them: besides, it was expressly done in the name of the Messiah, Acts 19:5 therefore they conclude he, or his forerunner, must be come; and that John must be one, or other of them, otherwise, why did he administer it? and it is also evident from hence, that no such practice had obtained before among them, or they would not have been alarmed at it, as they were; nor would they have troubled themselves to have sent after John, and inquire of him who he was, that should practise in this manner,
John Gill's commentary on John
In that day there shall be a fountain opened to the house of David and to the inhabitants of Jerusalem for sin and for uncleanness. Zechariah 13:1
Then will I sprinkle clean water upon you, and ye shall be clean: from all your filthiness, and from all your idols, will I cleanse you. Ezekiel 36:25
The Jewish leaders did know the Scriptures and apparently had connected these passages with the rite of baptism. Gill mentions the variety of baptisms, or ceremonial cleansings with which the Jews were very familiar and most certainly Johns actions would have alerted them to the spiritual and prophetical issues connected with the coming of the Messiah.