Concluding his teaching on sanctification, and before he moves on to practical application of that teaching, Paul gives a concise final comment on the matter in two brief statements.

The first refers to what has already taken place. Notice he refers to “those who belong to Christ Jesus.” They are the ones who have become believers in Christ through God’s grace. He has just spent two chapters (3 & 4) explaining and defending the doctrine of justification based on grace alone, apart from the works of the Law. Those who embrace this teaching are spoken of here as belonging to Christ Jesus. This is a relationship that was begun in the past, is a present reality and has enduring results. Christians are those who have come to faith in Christ, whose relationship with Him is not in doubt—because it does not depend on their own works of the Law, but on God’s grace. Grace removes doubt—thus one can speak of “belonging to Christ.”

If justification were by works of the Law, Paul would speak of Christ Jesus belonging to us. But, since it is by grace, the initiative belongs to Him, we are His to be reclaimed. And we have been reclaimed and given new life. It is God who justifies (Rom 8:33). Our role in justification is always referred to in the passive, we are those who are justified.  We belong to Him.

What is our role then? Two things. First, what we have already done, as believers, we “have crucified the flesh with its passions and desires.” This does not mean we never sin again, but it means we have abandoned all efforts of attaining righteousness through human efforts at keeping the Law—which only incites the passions and desires. We nailed them to the cross, as it were, we crucified them. Secondly, as those who belong to Christ, we are alive in the Spirit, having been justified. If that is true, and in fact it is true, then we should “walk by the Spirit.” The NIV translation captures the idea well, “Since we live by the Spirit, let us keep in step with the Spirit.” Our role as believers is not to sit back in a passive way. Just as we nailed our flesh to the cross, in agreement with the message of grace, we live in agreement with what the Spirit desires to do in our life. We walk in newness of life, cooperating with Him.

This is different from keeping in step with the Law: the motivation is different, the enabling  power is different, and the results are different. It’s all about grace!