Ambrose of Milan
Catena Aurea · Lukasevangelium 1
For he shall be great in the sight of the Lord, and shall drink neither wine nor strong drink; and he shall be filled with the Holy Ghost, even from his mother’s womb. And many of the children of Israel shall he turn to the Lord their God. And he shall go before him in the spirit and power of Elias, to turn the hearts of the fathers to the children, and the disobedient to the wisdom of the just; to make ready a people prepared for the Lord.
But we need no testimony that St. John turned the hearts of many, for to this point we have the express witness of both prophetic and and evangelical Scriptures. For the voice of one crying in the wilderness, Prepare ye the way of the Lord, and make His paths straight; and his baptisms thronged by the people, declare the rapid progress of conversion. For the forerunner of Christ preached, not himself, but the Lord; and therefore it follows, And he shall go before Him. It was well said, that he shall go before Him, who both in birth and in death was His forerunner.