John 1:25
And they asked him, and said unto him, Why baptizest thou then, if thou be not that Christ, nor Elias, neither that prophet? And they asked him, and said unto him, Why baptizest thou then, if thou be not that Christ, nor Elias, neither that prophet?
The question was put to John at Bethabara beyond the Jordan, where he was preaching and baptizing. Those who put it were priests and Levites sent from Jerusalem by the Jews, who were of the Pharisees, a delegation from the Jewish rulers and leaders, the Sanhedrin. They challenged his authority and right to baptize because he had denied being the Christ, Elijah, or the expected prophet, treating his public ministry as under their jurisdiction although he had not sought their approval.
The challenge arose because multitudes followed John from place to place, with even kings and nobles hearing him gladly, and his authoritative preaching and proclamation as messenger of the coming One directed attention to him as if he might be the Coming One, the promised Messiah, and to the listening people as if he might be the prophet Elijah. By that prophet they meant Moses, whom they thought might be raised from the dead and return, a belief prompted in part by John's knowledge of prophecy and Israel's wilderness history. The place itself fed deliverance hopes, since memories of God stopping the Jordan for Israel's crossing and of Jericho's overthrow stirred the people to hope God would again act powerfully to deliver Israel. The question exposes their one-sided study and limited view of the Messiah as a powerful prince, mighty prince, and great conqueror who would work powerfully in their behalf, so they were not drawn to Jesus because His mission and plain appearance did not match the greatness they expected.
John answered that he baptized with water but that One mightier than himself already stood among them unknown to them, coming after him yet preferred before him, whose shoe's latchet he was unworthy to stoop to unloose, using every opportunity to cut off hope centered on himself and to give a decided and unequivocal message that the long-promised Christ, the Messiah, was already among them. The exchange belongs to John's mission to prepare the way for Jesus and testify that He is the Christ, the Redeemer and Son of God, the Saviour of the world who takes away sin, joining the law and the prophets to the Christian dispensation by pointing back to the law and the prophets while pointing forward to Christ. The leaders had already received in Judea his testimony about Jesus' baptism and its accompanying divine signs, yet the question reflects their failure to recognize his preparatory role.