John 1:24

And they had been sent from the Pharisees. And they asked him and said unto him, Why then baptizest thou, if thou art not the Christ, neither Elijah, neither the prophet?

From the Pharisees ... This mention of that sect was to explain why the investigation continued with such persistence. Had only the Sadducees been involved, it is inconceivable that those hypocrites would have proceeded any further than John's admission that he was not the Messiah. Certainly, they would never have concerned themselves about any possibility of John's being Elijah raised from the dead! They did not believe in the resurrection. Therefore, John the apostle explained the extent and duration of the interview by noting the Pharisees' part in it.

It was the baptizing and not the preaching which caused the greatest perplexity in John's questioners. The extensive mass cleansing of the whole nation through repentance and baptism clearly suggested the great cleansing that had been prophesied by Ezekiel of the times of the Messiah (Ezekiel 36:25; 37:23); why then was John doing it if indeed he was not Christ nor the kind of forerunner they expected to precede the Christ? This query shows that they had missed completely the implication of John's quoting Isaiah 40:3, in which he made it clear that he was actually the forerunner of the Messiah, but not the literal Elijah they had expected.