“I indeed baptize you with water unto repentance: but he that cometh after me is mightier than I, whose shoes I am not worthy to bear: he shall baptize you with the Holy Ghost, and with fire:”
Matthew 3:11 — Greek Interlinear
Church Fathers on Matthew 3:11
As in the preceding words John had explained more at length what he had shortly preached in the words, 'Repent ye,' so now follows a more full enlargement of the words, 'The kingdom of heaven is at hand.'
John baptizes not with the Spirit but with water, because he had no power to forgive sins; he washes the body with water, but not at the same time the soul with pardon of sin.
For while as yet the sacrifice had not been offered, nor remission of sin sent, nor the Spirit had descended on the water, how could sin be forgiven? But since the Jews never perceived their own sin, and this was the cause of all their evils, John came to bring them to a sense of them by calling them to repentance.