And having said that his own baptism was only with water, he next shews the excellence of that baptism which was brought by Christ, adding, He shall baptize you with the Holy Spirit, and fire, signifying by the very metaphor which he uses the abundance of grace. For he says not, “He shall give you the Holy Spirit,” but He shall baptize you. And again, by the addition of fire, he shews the power of grace. And as Christ calls the grace of the Spirit, water, (John 4:14; 7:38.) meaning by water the purity resulting from it, and the abundant consolation which is brought to minds which are capable of receiving Him; so also John, by the word fire, expresses the fervour and uprightness of grace, as well as the consuming of sins.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: ubi sup.