He said therefore to the multitudes who went out to be baptized by him, "You offspring of vipers, who warned you to flee from the wrath to come?

 John had lived in the desert. The face of the desert was covered with stubble and brushwood, as dry as tinder. Sometimes a spark set the face of the desert alight and out from their crannies came the vipers, scurrying in terror from the menacing flames. It was to them John likened the people who came to be baptized. 