Matthew 3:11-12
11 “I baptize you with[m] water for repentance. But after me will come one who is more powerful than I, whose sandals I am not fit to carry. He will baptize you with the Holy Spirit and with fire. 12 His winnowing fork is in his hand, and he will clear his threshing floor, gathering his wheat into the barn and burning up the chaff with unquenchable fire.”
John, speaking to the people gathered by the rivers’ edge.
So, he says, “someone will come after me who will baptize you with the Holy Spirit and with fire.”
These things need an explanation to us – to me at least, but not to the listening audience. Or at least, not to the reading audience. Perhaps by the time Matthew is writing this book, he knows that his readers understand “baptism”, “Holy Spirit” and “with fire.”
If I recall correctly, baptism was not a new thing. Other cults and mystery religions also baptized their converts. So perhaps that was well-understood. But what about the Holy Spirit? There’s few references in the OT to the Holy Spirit. Maybe it was well-known among the Jewish literati. And finally, baptism with fire? The idea of “burning up the chaff” was well-known, and the prophets used similar imagery. But how to you baptize – a water-based activity – with fire?