Paul has just argued that grace outran sin, and now he answers the question his argument invites: 1"Are we to continue in sin that grace may abound?" If more sin brings more grace, why not sin freely? His reply is three words that stop the logic cold: 2"By no means!" Then he grounds it in a fact: 2"How can we who died to sin still live in it?"
The fact goes back to baptism, and Paul assumes his readers know what it means. We were 4"buried therefore with him." Baptism pictures a burial, and burial is total, with no part of the old life left above ground. Christ's tomb held a body truly dead, and Paul says our union with him in that death runs as deep.
Three times in this passage Paul uses the same small word: with. Buried with him, united with him, crucified with him. The whole argument depends on it. We were joined to him in his death, so what happened to him at the cross and the tomb happened to us. 6"Our old self was crucified with him," and the purpose was that we would no longer be enslaved to sin. Then Paul says, 7"For one who has died has been set free from sin." A dead slave owes his master nothing further. Death releases every debt.
Paul then turns to what is true of Christ now. Christ, raised from the dead, will never die again, and 9"death no longer has dominion over him." His death dealt with sin once for all, and his life now belongs entirely to God. Paul says the same two-part shape describes the believer: 11"So you also must consider yourselves dead to sin and alive to God in Christ Jesus." "Consider" is the accounting word Paul used in chapter 4 for Abraham's faith counted as righteousness. Here it becomes something believers do, reckoning as true what God has already done, whether or not it feels true on a given day.
From there Paul moves to the body: 12"Let not sin therefore reign in your mortal body." The word for "instruments" in verse 13 can also mean weapons, the language of a soldier reporting for duty. Every body is enlisted somewhere. The open question is which master it serves.
Then comes the promise: 14"For sin will have no dominion over you, since you are not under law but under grace." Sin can still knock and tempt and accuse. It no longer owns the house. That is why Paul can tell believers to act from freedom. A freed slave still has to decide whether to walk back through the old master's door, and grace leaves sin able to tempt and unable to compel.
Where do you feel sin's old claim most strongly? Paul's instruction is to reckon, to count the account as settled and then act from that. The burial is behind you, and so is the debt.
Prayer
Father, thank you for uniting us to Christ so completely that his death became our death and his life is becoming ours. Where sin still tempts us to act like slaves who were never freed, help us consider ourselves what you have declared us to be, dead to sin and alive to you. Take our bodies and our whole selves and use them as instruments for righteousness. In Jesus' name, amen.