From the Word
1 I mean that the heir, as long as he is a child, is no better than a slave, though he is the owner of all the estate; 2 but he is under guardians and trustees until the date set by the father. 3 So with us; when we were children, we were slaves to the elemental spirits of the universe. 4 But when the time had fully come, God sent forth his Son, born of woman, born under the law, 5 to redeem those who were under the law, so that we might receive adoption as sons. 6 And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” 7 So through God you are no longer a slave but a son, and if a son then an heir.
Galatians 4:1–7, RSV
In the article of faith, in which we say that the Son of God became man and that he was of the same nature as we ourselves are, in order that he might redeem us from sin and death and give us eternal life without any merit or worthiness of our own, we give Jews and Turks no less occasion for laughter and mockery than when we speak of the three persons in the Godhead. For this is a more absurd assertion by far, in the estimation of human reason, which speculates in its Jewish and Turkish, yea, heathenish teachings, on this wise: God is an only, almighty Lord of all, who has created all men and given them the law according to which they are to live; accordingly it follows that he will be merciful to the good and obedient, but will condemn and punish the disobedient. Therefore he who does good works and guards himself against sin, God will reward. These are nothing but heathenish conclusions drawn from earthly, worldly experience and observation.
Such heathen ideas of wisdom, holiness and service of God are taught and practiced by the pope. So we believed, myself and others, while we were under him, not knowing any better; otherwise we would have done and taught differently. In fact, he who has not this revelation and Word of God, can neither believe nor teach other than pagan doctrine. For human reason knows no better; and how can it know better without the revelation? Even when the revelation was proclaimed, human wisdom would not heed it, but despised it and followed its own fancies.
But to us this counsel and mind of God, in giving his Son to take upon himself our flesh, is revealed and declared. From the Word of God we have the knowledge that no man of himself can be righteous before God; that our whole life and all our deeds are under wrath and condemnation, because we are wholly born in sin and by nature are disobedient to God; but if we would be delivered from sin and be saved, we must believe on this mediator, the Son of God, who has taken our sin and death upon himself, by his own blood and death rendering satisfaction, and has by his resurrection delivered us.
Luther, Martin, and John Sander. Devotional Readings from Luther’s Works for Every Day of the Year. Augustana Book Concern, 1915, pp. 427–28.