16 “The law was given by Moses: grace and truth came by Jesus Christ.” By a servant was the law given, and made men guilty: by an Emperor was pardon given, and delivered the guilty. “The law was given by Moses.” Let not the servant attribute to himself more than was done through him. Chosen to a great ministry as one faithful in his house, but yet a servant, he is able to act according to the law, but cannot release from the guilt of the law. “The law,” then, “was given by Moses: grace and truth came by Jesus Christ.”
Source: Tractates on the Gospel of John (New Advent)