Origen

(in Joan. tom. vi. c. 7) He answers then the Levites and Priests, I am not, conjecturing what their question meant: for the purport of their examination was to discover, not whether the spirit in both was the same, but whether John was that very Elias, who was taken up, now appearing again, as the Jews expected, without another birthI. But he whom we mentioned above as holding this doctrine of a reincorporation, will say that it is not consistent that the Priests and Levites should be ignorant of the birth of the son of so dignified a priest as Zacharias, who was born too in his father’s old age, and contrary to all human probabilities: especially when Luke declares, that fear came on all that dwelt round about them. (Luke 1:65) But perhaps, since Elias was expected to appear before the coming of Christ near the end, they may seem to put the question figuratively, Art thou he who announcest the coming of Christ at the end of the world? to which he answers, I am not. But there is in fact nothing strange in supposing that John’s birth might not have been known to all. For as in the case of our Saviour many knew Him to be born of Mary, and yet some wrongly imagined that He was John the Baptist, or Elias, or one of the Prophets; so in the case of John, some were not unacquainted with the fact of his being son of Zacharias, and yet some may have been in doubt whether he were not the Elias who was expected. Again, inasmuch as many prophets had arisen in Israel, but one was especially looked forward to, of whom Moses had prophesied, The Lord thy God will raise up unto thee a Prophet from the midst of thee, of thy brethren, like unto me; unto Him shall ye hearken: (Deut. 18, 15) they ask him in the third place, not simply whether he is a prophet, but with the article prefixed, Art thou that Prophet? For every one of the prophets in succession had signified to the people of Israel that he was not the one whom Moses had prophesied of; who, like Moses, was to stand in the midst between God and man, and deliver a testament, sent from God to His disciples. They did not however apply this name to Christ, but thought that He was to be a different person; whereas John knew that Christ was that Prophet, and therefore to this question, he answered, No.