The operative noun in Rom 8:12 is ὀφειλέτης (opheiletés) which occurs just seven times in the NT, namely, Matt 6:12, 18:24, Luke 13:4, Rom 1;14, 8:12, 15:27, Gal 5:3. Its meaning, according to BDAG is:
- one who is in debt in a monetary sense, debtor, with the amount of the debt given in general, eg, Matt 18:24
- one who is under obligation in a moral or social sense, one under obligation, one liable for
- (a) debtor: we are all debtors in the matter of sin, Pol 6:1
- (b) one who is obligated to do something, eg, Rom 15:27, 1:14, 8:12, Gal 5:3
- (c) one who is guilty of a misdeed, one who is culpable, at fault, eg, Matt 6:12, Luke 13:4
Thus, Paul's meaning in Rom 8:12 appears similar to that elsewhere in the same epistle, that he (and all Christians) should feel an obligation to live according to the Spirit and not according to the flesh. That is, Paulis contrasting the life lived according to the flesh (the natural desires) vs those who live according to the Spirit.
This contrast, between the life according to the flesh vs life according to the Spirit, is set out in the table below as taken from Rom 8:4-11 (see appendix below)
|Life according to the Spirit
|Life according to the Flesh
|Law standard fulfilled
|Law standard not fulfilled
|set minds on the Spirit
|set minds on things of the flesh
|mind is life and peace
|mind is death
|mind not hostile to God, submits to God's law, pleases God
|mind hostile to God, does not submit to God's law, cannot please God
|controlled by the Spirit
|controlled by the flesh
|belongs to Christ
|does not belong to Christ
|body is dead and spirit is alive
|body is not dead but spirit is dead
|Christ's Spirit lives in these people & gives life
|Christ's Spirit does not live in these people
|have obligation to live according to the Spirit
|live according to the flesh
|will live and put to death the deeds of the body
|will die when living by the deeds of the flesh
|are called sones of God
|not sons of God
This is a regular theme in the NT – continue the decision made at conversion to be sanctified (set apart) for Christ. That is, the continuing decision to be set apart for Christ results in a changed life and new "deeds" via the miraculous work of God.
- But we know that when he appears, we shall be like him, for we shall see him as he is. Everyone who has this hope in him purifies himself, just as he is pure. 1 John 3:2, 3
- But if anyone does not have them, he is nearsighted and blind, and has forgotten that he has been cleansed from his past sins. Therefore, my brothers, be all the more eager to make your calling and election sure. For if you do these things, you will never fall. 2 Peter 1:9, 10.
- But you, man of God, flee from all this, and pursue righteousness, godliness, faith, love, endurance and gentleness. Fight the good fight of the faith. Take hold of the eternal life to which you were called when you made your good confession in the presence of many witnesses. 1 Tim 6:11, 12.
- We were therefore buried with him through baptism into death in order that, just as Christ was raised from the dead through the glory of the Father, we too may live a new life. Rom 6:4.
- Therefore, I urge you, brothers, in view of God's mercy, to offer your bodies as living sacrifices, holy and pleasing to God--this is your spiritual act of worship. Do not conform any longer to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God's will is – his good, pleasing and perfect will. Rom 12:1, 2.
- Since we have these promises, dear friends, let us purify ourselves from everything that contaminates body and spirit, perfecting holiness out of reverence for God. 2 Cor 7:1.
- Instead, speaking the truth in love, we will in all things grow up into him who is the Head, that is, Christ. From him the whole body, joined and held together by every supporting ligament, grows and builds itself up in love, as each part does its work. Eph 4:15, 16.
- But one thing I do: Forgetting what is behind and straining toward what is ahead, I press on toward the goal to win the prize for which God has called me heavenward in Christ Jesus. Phil 3:13, 14.
- So then, just as you received Christ Jesus as Lord, continue to live in him, rooted and built up in him, strengthened in the faith as you were taught, and overflowing with thankfulness. Col 2:6, 7.
- Epaphras…is always wrestling in prayer for you, that you may stand firm in all the will of God, mature and fully assured. Col 2:12
- His divine power has given us everything we need for life and godliness through our knowledge of him who called us by his own glory and goodness. Through these he has given us his very great and precious promises, so that through them you may participate in the divine nature and escape the corruption in the world caused by evil desires. 2 Peter 1:3, 4.
- Therefore, dear friends, since you already know this, be on your guard so that you may not be carried away by the error of lawless men and fall from your secure position. But grow in the grace and knowledge of our Lord and Saviour Jesus Christ. 2 Peter 3:17, 18
APPENDIX - Rom 8:4-14
4 ...so that the righteous standard of the law might be fulfilled in us, who do not walk according to the flesh but according to the
5 Those who live according to the flesh set their minds on the things of the flesh; but those who live according to the Spirit set
their minds on the things of the Spirit. 6 The mind of the flesh
is death, but the mind of the Spirit is life and peace, 7 because
the mind of the flesh is hostile to God: It does not submit to God’s
law, nor can it do so. 8 Those controlled by the flesh cannot
9 You, however, are controlled not by the flesh, but by the Spirit, if the Spirit of God lives in you. And if anyone does not have
the Spirit of Christ, he does not belong to Christ. 10 But if
Christ is in you, your body is dead because of sin, yet your spirit is
alive because of righteousness. 11 And if the Spirit of Him who
raised Jesus from the dead is living in you, He who raised Christ
Jesus from the dead will also give life to your mortal bodies through
His Spirit, who lives in you.
12 Therefore, brothers, we have an obligation, but it is not to the flesh, to live according to it. 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.