Finally they said, "Who are you? Give us an answer to take back to those who sent us. What do you say about yourself?"
Even at this stage the ruling council of the Jews were worried. This delegation had been sent to John because he was behaving strangely and drawing crowds. Baptism had no tradition in the Old Testament, though it was practised at Qumran. Some authorities think that John had spent some time there but there is no evidence to support this theory.
Some authorities think that they had been sent on a mission to root out false prophets or like the Spanish Inquisition to seek out heretics. However, at this stage of his ministry John had a lot of popular support and could not be arrested without an uprising. The delegation had to tread carefully, hence the polite questioning - compare this with the treatment that Jesus received when questioned. Torture was as prevalent then as it is now.