The main argument employed by those who don’t think that Romans 7 is describing the experience of believers is simply that in Romans 6 Paul has described believers as dead to sin (6:2), crucified with Christ and no longer enslaved to sin (6:6), and thus, having died, believers are set free from sin (6:7). These things being the case, it is argued that when Paul writes in Romans 7 of the one who is “sold under sin” (7:14) and serving the law of sin in the flesh (7:25), he cannot be describing believers.
There are several reasons I find this unpersuasive. There are probably more than the ones I will articulate here, but these are the ones that come to mind (influenced by Tom Schreiner’s commentary on Romans and John Piper’s sermon on Romans 7).
(1) Having described the way that believers have been freed from sin through union with Christ in his death in Romans 6:1–10, Paul commands believers in 6:11, “So you also must consider yourselves dead to sin and alive to God in Christ Jesus” (ESV). This tells us that while there is a positional reality that has been described in 6:1–10, there is an ongoing process of “mental transformation” (12:1–2) that still needs to happen in the experience of believers. Believers must “reckon” themselves dead to sin, and this “reckoning” is described with the same Greek verb used repeatedly in Romans 4 to describe Abraham being “reckoned” righteous not because of what he had done but according to grace (e.g., 4:3–5). So it seems to me that just as Abraham was “reckoned” righteous by faith in spite of his sin, so also believers must “reckon” themselves dead to sin even though they will groan til the day when they are set free from corruption (8:18–25). Why does Paul have to command believers to “reckon” themselves dead to sin? Because of the reality he names in Romans 7:17, 20, and 23—indwelling sin. (See also the command in 6:19, and the reasoning in 6:20–22).
(2) Why would Paul use the first person singular pronoun (“I”) in Romans 7 if he were not describing a reality that he himself experiences? Is there another place in Paul’s writings where he speaks in the first person singular (“I”) but is really not describing himself? The pervasive use of the first person singulars (“I” “me” “my”) and the lack of any indication that Paul is not describing himself argues against the position that Paul is not, in fact, describing himself.
(3) The poignancy of the anguished statements in 7:24–25 should be taken as indicative of Paul’s own feelings (Compare his anguish in 9:1–3). If the desperate cry, “Wretched man that I am! Who will deliver me from this body of death?” in 7:24 is not describing Paul’s own experience, don’t these words seem a little melodramatic? Wouldn’t it be more typical of Paul to describe the inability of unbelievers in a more detached way as we see in Rom 8:7, 1 Cor 2:14, or 2 Cor 4:4?
(4) If Paul is not describing his own experience as a Christian in Romans 7, he sure confuses the matter with the concluding words of the chapter: “So then, I myself serve the law of God with my mind, but with my flesh I serve the law of sin” (7:25b). If Paul meant to describe the experience of an unbeliever, which culminates in the wretched cry in 7:24 (“Who will rescue me?”), shouldn’t the opening words of 7:25 (“Thanks be to God through Jesus Christ our Lord!”) be followed by a Romans 6 type affirmation? In other words, the answer to the cry in 7:24 is given in 7:25a—Jesus will rescue me from this body of death, thank God! If Paul has been describing an unbeliever, why doesn’t Rom 7:25b read like Rom 6:7? Shouldn’t 7:25b, according to this interpretation, read more on the lines of: “now you’ve died with Christ and you’re set free from sin!”?
I submit, then, that the reason Paul has to write Romans 6 at all, the reason he has to command the Roman believers to “reckon” themselves to be what they (positionally in Christ) are in 6:11, is explained in Romans 7. In Romans 6, Paul introduces some of the only commands in all of Romans 1–11 because believers find themselves in the conflicted state described in Romans 7—we want to do good but we often do what we hate instead (cf. 7:15, 16, 18, 19, 20, 21, 22, 23, 24, 25).
The answer to this dilemma is then explained in Romans 8:1–17, where Paul describes the difference between living according to the flesh and living according to the Spirit. Those who walk according to the Spirit will indeed “fulfill the law” (8:4), but this walking according to the Spirit entails putting to death the “deeds of the body” by the power of the Spirit (8:13). Here again, these “deeds of the body” have to be “put to death” because they arise from the “indwelling sin” described in Romans 7.