‘John answered, saying to them all, “I indeed baptise you with water, but there comes he who is mightier than I, the latchet of whose sandals I am not worthy to unloose. He will baptise you in the Holy Spirit and in fire, Whose winnowing-fork is in his hand, thoroughly to cleanse his threshing-floor, and to gather the wheat into his garner, but the chaff he will burn up with unquenchable fire.”
John denies that he is the Messiah completely and effectively. He points out that he merely baptises with water, an act of symbolism which indicates to God that the person is seeking to be transformed by the Spirit. But that is all that he can do. One, however, is coming Who is far mightier than he is, One Whose sandals he is not fit to unstrap. Unstrapping sandals was seen as the task of a the meanest of slave, even of a non-Jewish slave (the feet were dirty and smelled). It was the one task that the disciple of a Rabbi could not be expected to demean himself to do. Yet, in the case of Jesus, John does not even see himself as worthy to do that.
‘One Who is mightier.' We have already seen that Jesus was called ‘The Great' without any limitation (Luke 1:32). Now He is ‘the Stronger One'. We can compare this with Luke 11:22 where Jesus as ‘the Stronger than he' defeats and renders powerless Satan. There is a building up of new titles in order to describe the Coming One. John is a prophet, even another Elijah, but he pales into insignificance beside this ‘Stronger One'. There has never been anyone on earth who compares with Him.
And when He comes He will of Himself ‘drench' men and women with the Holy Spirit and with fire (baptizo = inundate, overwhelm, drench and is here used as if fire was a liquid). In the text the association of the two is as close as can be, ‘drench in the Holy Spirit and fire'. The meaning of this is then immediately made clear. He will act as the divider of the people (compare Matthew 7:13-14; Matthew 13:49-51; Matthew 25:31-46; Isaiah 66:22-24; Daniel 12:1-2). With His winnowing fork, the fork used to toss the coarse grain into the air so as to separate the wheat from the chaff by means of the prevailing wind, He will separate them, gathering the righteous into His barn and destroying the non-righteous in burning and consuming flames. And it will be no good hoping that somehow it will not happen and that there may be a way of escape, for the flames which He will use are unquenchable.
That fire here primarily refers to the fire of judgment rather than fire of purifying would seem to be emphasised by the fact that fire all the way through refers to judgment. Vipers flee from fire. The unfruitful trees are burned in fire. The chaff is burned up with fire, and that in close association with ‘baptise in the Holy Spirit and fire'. But for the righteous it could also indicate a fire of purifying. There is something ominous about the fact that the same Holy Spirit can be a Spirit of life and purifying and a Spirit of burning and destruction (Isaiah 4:4). For part of the cleansing results from the removal of the unclean. When the gold is purified in the flames, the dross is removed and destroyed. (In the Old Testament the fires also both refined and destroyed. When His fires came some passed through them and were purified, others were destroyed in the same fires).
So the choice put before them is clear. They must either respond to the Spirit's working in their lives, or face the judgment of God. If they do the one it must and will result in changed and transformed lives, if they do the other their end is destruction. If someone cavil at the mention of the Spirit's work in connection with John's preaching we have only to remember that John preaches as one who is full of the Holy Spirit. Thus any effectiveness he has comes through the Spirit's working.
In the chiasmus these verses about the people, the tax collectors and the soldiers are paralleled with the earlier quotation from Isaiah in Luke 3:4-6. Here then is the way in which the way must be prepared, here is what must be carried into effect. Here is how they may ‘see the salvation of God', for that salvation is found in the One Who is coming.
The idea of the Messiah as baptising in the Holy Spirit probably came to John from Isaiah 52:15 where the Exalted One of Luke 3:13 will ‘sprinkle the nations', conjoined with Ezekiel 36:25-27 where the sprinkling indicates the work of the Spirit in men's hearts. He may then have connected this with Isaiah 32:15; Isaiah 44:1-6. If the Spirit of Moses could be passed on to the seventy elders, and Elijah could be involved in arranging the passing on of his Spirit to Elisha (2 Kings 2:10), it is not a large step to the Messiah, Who is the Son of the Most High, passing on His Spirit to all His people, for all His people were going to be prophets (Joel 2:28-29).
John is not so unlike Jesus as is often suggested. It is easy when looking at the teaching of Jesus to only see the teaching that we like, but if we ignore His teaching on judgment we misrepresent Him. For Jesus' teaching on judgment is even more severe than that of John. All the most fearsome of teaching comes on His lips (Luke 10:14; Luke 12:4; Luke 13:28; Luke 16:23-24; Matthew 5:21-29; Matthew 11:24; Matthew 13:49-51; Matthew 18:7-9; Matthew 25:46; Mark 9:43-48)