From the Word
4 Such is the confidence that we have through Christ toward God. 5 Not that we are competent of ourselves to claim anything as coming from us; our competence is from God, 6 who has made us competent to be ministers of a new covenant, not in a written code but in the Spirit; for the written code kills, but the Spirit gives life.
2 Corinthians 3:4–6, RSV
These words are blows and thrusts at the false apostles and preachers. We rely not upon ourselves or our wisdom and ability, Paul would say; we preach not what we ourselves have invented. But this is our boast and trust in Christ before God, that we have made of you a divine epistle; have written upon your hearts, not our thoughts, but the Word of God. We are not glorifying our own power, but the works and power of him who has called and equipped us for such an office; from whom proceeds all you have heard and believed.
It is a glory which every preacher may claim, to be able to say with full confidence of heart: This trust have I toward God in Christ, that what I teach and preach is truly the Word of God. Likewise when he performs other official duties in the Church — baptizes a child, absolves and comforts a sinner — it must be done in the same firm conviction that such is the command of Christ. Who would teach and exercise authority in the Church without this glory, “it were better for him that a millstone were hanged about his neck, and that he were drowned in the depths of the sea.” For the devil’s lies is what he preaches, and death is what he effects.
God puts into our heart and mouth what we should say, and impresses it upon your heart through the Holy Spirit. We cannot ascribe to ourselves any honor, cannot seek our own glory as the self-instructed, proud spirits do; me must give to God the honor, and must glory in the fact that by his grace and power he works in you unto salvation through the office committed unto us. Nothing should be taught and practiced in the Church but what is unquestionably God’s Word. Man’s achievements, man’s reasoning and power, are of no avail in spiritual matters save in so far as they come from God. For it is of no moment that men observe our greatness and ability; the important thing is that poor souls may rest assured of being presented with God’s Word and works, whereby they may be saved.
Luther, Martin, and John Sander. Devotional Readings from Luther’s Works for Every Day of the Year. Augustana Book Concern, 1915, pp. 289–90.