Matthew 3:14 and Matthew 3:15 are peculiar to St. Matthew. But John. In John 1:31, John 1:33 the Baptist says that he knew him not till the descent of the Holy Spirit; i.e. knew him not in his full Messianic character.
Here, either by an involuntary and miraculous impression, psychologically due to the previous revelation he had received (cf. Meyer); or, as is on the whole more probable, from his previous knowledge, direct or indirect, of Jesus, he recognizes his superior sanctity.
John's inmost thoughts must therefore have been somewhat as follows. "I have come to announce the advent of Messiah; hero is One who is much holier than I it may be that he is Messiah, but I have no certainty till the sign promised has been vouchsafed."
Forbade; would have hindered (Revised Version), for διεκώλυεν, does not in itself imply speech. (For a similar imperfect of that which was not fully carried out, cf. Luke 1:59.) It is noticeable, though doubtless merely as a coincidence, that the strong compound word διακωλύω and βαπτίζομαι also occur together in Judith 12:7.
I have need to be baptized of thee. Many see here a reference to the baptism of the Spirit and fire, mentioned in verse 11. But the following clause, "and dost thou come to me?" implies that the baptisms are identical, viz.
baptism by water. The sentence is equivalent to "I John, who myself administer the baptism of repentance, need to profess repentance myself, and ought rather, therefore, to receive such a baptism at thy hands, who art so far holier than I" (cf.
further Weiss, 'Life,' 1.320).