John Calvin Commentary John 1:25

"And they asked him, and said unto him, Why then baptizest thou, if thou art not the Christ, neither Elijah, neither the prophet?" — John 1:25 (ASV)

Why then do you baptize? By establishing those three categories, they appear to form a very conclusive argument: if you are not the Christ, nor Elijah, nor a prophet; for it is not for everyone to institute the practice of baptism.

The Messiah was to be one who possessed all authority. Concerning Elijah who was to come, they had formed this opinion, that he would commence the restoration of both the royal authority and the Church. The prophets of God, they readily grant, have a right to discharge the office committed to them.

They conclude, therefore, that for John to baptize is an unlawful novelty, since he has received no public position from God.

But they are wrong in not acknowledging him to be that Elijah who is mentioned in Malachi 4:5; though he denies that he is that Elijah of whom they foolishly dreamed.