From the Word
12 So then, brethren, we are debtors, not to the flesh, to live according to the flesh— 13 for if you live according to the flesh you will die, but if by the Spirit you put to death the deeds of the body you will live. 14 For all who are led by the Spirit of God are sons of God. 15 For you did not receive the spirit of slavery to fall back into fear, but you have received the spirit of sonship. When we cry, “Abba! Father!” 16 it is the Spirit himself bearing witness with our spirit that we are children of God, 17 and if children, then heirs, heirs of God and fellow heirs with Christ, provided we suffer with him in order that we may also be glorified with him.
Romans 8:12–17, RSV
This is a noble and comforting text, worthy of being written in letters of gold. Because ye now through faith, he means to say, have the Holy Spirit and are led by him, ye are no longer in bondage as ye were when under the law; ye need no longer be afraid of its terrors and its demands, as if God would condemn and reject you on account of your unworthiness and the remaining infirmity of your flesh. But ye have the consolation that, through faith, ye have the assurance of God’s grace, and may consider God your Father and call upon him as his children.
Paul speaks of the “spirit of bondage” and the “spirit of adoption” according to the customs of his times. In those days man-servants and maid-servants were the property of the master of the house in the same sense that a cow was his property. He bought them with his money; he did with them as he pleased, just as with his cattle. They were afraid of their master and had to expect stripes, imprisonment and punishment even unto death. They could only say: Here I serve for my bread only; I have nothing to expect but stripes, and must be content to have my master cast me out or sell me to some one else whenever he chooses. They could never have a well-grounded hope of release from such fear and bondage and coercion.
Such a slavish, captive, fearful and uncertain spirit ye do not have, says the apostle. Ye are not compelled to live continually in fear of wrath and condemnation as are the followers of Moses and all who are under the law. On the contrary, ye have a delightful, free spirit, one confident and contented, such as a child entertains toward its father, and ye need not fear that God is angry with you or will cast you off and condemn you. For ye have the Spirit of his Son in your hearts and know that ye shall remain in his house and receive the inheritance, and that ye may comfort yourselves with it and boast of it as being your own.
Luther, Martin, and John Sander. Devotional Readings from Luther’s Works for Every Day of the Year. Augustana Book Concern, 1915, pp. 321–22.