12 So then, brothers, 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 adoption as sons, by whom we cry, “Abba! Father!” 16 The Spirit himself bears 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 (ESV)
I read and re-read this passage always waiting for the other shoe to drop. I’m not a debtor to the flesh…. Wait, then what am I a debtor to? Frankly, I think the passage might have been better translated if it read “we are not debtors to the flesh, to live according to the flesh.” But no one asked my opinion, and I would be suspicious of a translator that did. This however is the meaning of the text. Paul refuses to say that we are debtors to the Spirit of God, the other shoe never drops.
A debtor was one basically enslaved to another who ruled over him who reigned over him. This is no longer our relationship to the flesh in which we still live. Instead we have been set free by the Son, and so we are free indeed. We are now sons of God. We are his children, and children, though they may for a time be entrusted to guardians and masters until the time set by his father, they are not slaves (Gal. 4:1ff.) We are heirs. Sin, death, the devil, our own flesh no longer rule or reign over us. They no longer have claim over us. No, we are not slaves but heirs. We are not debtors but free. Now for us to live is Christ, to die is gain. So now we suffer not as slaves to the flesh in which we live, but as members of the body of Christ who is our head. Our suffering is his suffering, that his glorification would be our glorification.