John Gill

I indeed have baptized you with water,.... This was spoken to the baptized persons, partly to take off their dependence upon him and his baptism; and partly to direct their views to Christ, from whom the gifts and graces of the Spirit are alone to be had: but he shall baptize you with the Holy Ghost; See Gill on Mat 3:11. One copy adds, "and with fire", as there: a Jewish writer says, the holy blessed God baptizeth with fire, and the wise shall understand (p). (p) R. Menachem in Lev. viii. apud Ainsworth on Gen. xvii. 12.