Luke 3:16
John answered, saying unto them all, I indeed baptize you with water; but one mightier than I cometh, the latchet of whose shoes I am not worthy to unloose: he shall baptize you with the Holy Ghost and with fire:
John answered, saying unto them all,.... For some of them might not only so think in their hearts, but express with their mouths the apprehension they had of him; and might put the question to him, as the priests and Levites from Jerusalem afterwards did; or he might know the secret thoughts of their hearts by divine revelation; or be apprized by his disciples of the private sentiments of the people concerning him: and therefore, to put them out of doubt, and that he might not have an honour conferred on him, which did not belong to him, he addressed himself, in a very public manner, to the whole multitude, in the hearing of them all: though the word "all" is left out in the Syriac and Persic versions, but rightly retained in others, being in all copies, and having a considerable emphasis on it: and said the following words.
I indeed baptize you with water; Matthew adds "unto repentance"; upon the profession of repentance:
but one mightier than I cometh; that is, after me; as Matthew records it:
the latchet of whose shoes I am not worthy to unloose; neither to bear his shoes after him, as Matthew says, nor to untie his shoe string, or unbuckle his shoe, both which were menial actions with the Jews: he shall baptize you with the Holy Ghost, and with fire; as he did some of their nation, his own disciples, on the day of pentecost;
See Gill on "Matthew 3:11"