{To the multitude that went out} (	ois exporeuomenois
ochlois). Plural, {Multitudes}. The present participle also
notes the repetition of the crowds as does elegen (imperfect),
he used to say.  Mt 3:7-10  singles out the message of John to
the Pharisees and Sadducees, which see for discussion of details.
Luke gives a summary of his preaching to the crowds with special
replies to these inquiries: the multitudes,  10,11 , the
publicans  12,13 , the soldiers  14 . {To be baptized of him}
(aptisth(886e)ai hup' autou). This is the purpose of their coming.
 Mt 3:7  has simply "to his baptism." John's metaphors are from
the wilderness (vipers, fruits, axe, slave boy loosing sandals,
fire, fan, thrashing-floor, garner, chaff, stones). {Who warned
you?} (	is hepedeixen humin;). The verb is like our "suggest"
by proof to eye, ear, or brain ( Lu 6:47  12:5  Ac 9:16  20:35  Mt 3:7 ). Nowhere else in the N.T. though common ancient word
(hupodeiknumi, show under, point out, give a tip or private
hint).