The following is a quote from Johannes Brenz’ Commentary on St. John, 1529. It wonderfully confesses what we have in Christ, the blessings of Law and Gospel and their fruit.
“For the law was given through Moses, but grace and truth came through Jesus Christ” (John 1:17 NKJV).
LAW THROUGH MOSES, etc.
The Word of God has two offices:* to kill and make alive; to show sin, and remit sin; to work wrath, and declare grace; to show what is right, and to give justification. It kills, shows sin, works wrath, and shows what is right through the Law. It vivifies, remits sin, declares grace, and bestows justification through the Gospel. The Law, however, has been presented through Moses, but the Gospel through Christ. These, indeed, are the two preachers renowned in the world. Furthermore, both the Prophets and the Apostles have preached, but some preaching the Law from Moses, others announcing the Gospel from Christ. But both these preachers are necessary for justification: first Moses, then Christ. Namely, Moses without Christ drives to despair. Christ or the Gospel without Moses makes secure men and despisers. For, to the highest degree possible, they, for whom sin has not yet been revealed through the Law, hear the grace of the Gospel, take with it a certain carnal liberty, saying, “Now I shall sin with impunity, because sins do not damn, and hell has been extinguished.” It is that which is objected even by Paul in Romans 6: “Shall we sin because we are not under the Law, but under grace;” and “shall we remain in sin so that grace may abound;” and “let us do evil so that good may comes from it.” Therefore, so that the right order of justifying is served, both preachers ought, by necessity, to be heard, both Moses and Christ: Moses, so that through the Law he may kill, show slanders, declare wrath, and teach us so that we may certainly know that no powers (nihil virium) or accomplishments (efficacium) toward justification or salvation are in us; Christ, so that through the Gospel we may again be vivified, restored into grace, and acquire the powers of working the things which the Law commands. Hence, through the speech of Christ we are free from the Law, not that it should not be done, but rather that it may be done. For Christ says, “I came not to dissolve the Law, but to fulfill.” And Paul, “Through faith we establish the Law.”** For what the Law could not fulfill, that part, which was weak through the flesh, God fulfilled by sending His own Son under the form of flesh liable to sin. And this is what he says, “Grace and Truth came forth through Jesus Christ.” For Moses through the Law declares that we are slanders, condemned, and sons of God’s wrath, but Christ restores us again into the grace of God, and fulfills that which was promised before. Justification was promised. Eternal life was promised. But these have been abundantly supplied through Christ.
* “The Offices of God’s Word.”
** “Christ frees us from the Law.”