Theophylact of Bulgaria
For the manner in which the forerunner prepared the way of the Lord he explains, adding, To give knowledge of salvation. The Lord Jesus is salvation, but the knowledge of salvation, i. e. of Christ, was given in John, who bore witness of Christ.
For in no other way was He known to be God, but as having forgiven the sins of His people. For it is of God alone to forgive sins.