Alcuin of York — as excerpted in the Catena Aurea on John 1:6-8

“That is, the grace of God, or one in whom is grace, who by his testimony first made known to the world the grace of the New Testament, that is, Christ. Or John may be taken to mean, to whom it is given: because that through the grace of God, to him it was given, not only to herald, but also to baptize the King of kings.”