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 ('the') Christ, nor Elias, neither that ('the') prophet? Thinking that he disclaimed any special connection with the Messiah's kingdom, they very naturally demand his right to gather disciples by baptism. (See the note at John 3:28.)