In The Deliverance of God: An Apocalyptic Rereading of Justification in Paul (Eerdmans 2013), Douglas A. Campbell has provided a radical reinterpretation of Romans 1:18–3:20 (among other texts) that makes Paul a more coherent writer and a brilliant rhetorical one at that — but that makes his interpreters throughout church history profoundly misguided.
A good way to start off is to note a few things that make Romans 1:18–3:20 unique in Paul:
- Firstly, Paul repeatedly uses the classical rhetorical device of the diatribe, i.e., he describes the position of a rhetorical (but not necessarily imaginary!) opponent, which allows him to engage that person’s position and effectively win the argument (if he does it well, of course). Paul does this three times in this passage (2:1–5, 17–29; 3:1–9; see also 3:27–31), which is quite unique: the other primary diatribes in Paul can be found in Rom 9:19–20 (not unrelated!) and 1 Cor 6:12–14; 15:35–36.
- Secondly, Paul uses a lot of Jewish material in these chapters. The influence of Wisdom of Solomon 13–14 on Rom 1:18–32 has long been recognised. Moreover, 2:3 seems to be a reference to Psalms of Solomon 15:8, and 2:4 contains allusions to Wisdom of Solomon 11:23; 12:10; 15:1. Furthermore, as Richard Longenecker has argued in his masterful commentary on Romans,  Paul uses Jewish aphorisms or the like in 2:2, 11; 3:4a, 6. Also, 2:7–10 can be designated as Jewish hymnic material due to the antithetical, parallelistic structure (so Longenecker). Lastly, there are references or allusions to Scripture in 1:23–26 (Genesis 1:20–22, 24-28, 30), 2:6 (Ps 62:12; Pro 24:12), 24 (Isaiah 52:5/Ezekiel 36:20-23), 3:4 (Psalm 51:4), and of course the catena of texts in 3:10–18. 
- Thirdly, and following from the previous points, there are a lot (I mean, a lot) of Pauline hapax legomena, i.e., words that do not occur in any other passages in the Pauline corpus. Also, there are what I would call ‘semantic’ hapax legemona, i.e., words that Paul does not use in this sense anywhere else, and finally there are words that are only used here elsewhere in an allusion to or quotation of Scripture (thus probably not being a part of Paul’s own vocabulary). If we only look at 1:18–32, these three categories already add up to 43 (!) unique or very rare words (26/11/6). 
- Fourthly, as Campbell shows extensively, there are many intrinsic, systematic, empirical, and exegetical problems with the traditional reading of 1:18–3:20 — i.e., as a ‘leveling of the field’, establishing that everyone is sinful and meriting punishment, thus making the way for the gospel, which consists of Jesus taking the penalty so that believers can be acquitted.  Especially the commitment to God’s impartial judgment on the basis of desert in 2:6–11 (which consists of doing Torah! — 2:13), with little role for Christ, God’s love, or transformation, clashes with Paul’s theological commitments as we read them elsewhere, especially in chapters 5–8.
Now, you gotta read Campbell (even though it’s a lot — believe me: I know) to see the extensive problems that necessitate a new reading. In this article, I just want to show in six steps how we can reach such a new, rhetorical reading of Romans 1:18–3:20.
A New Reading in 6 Steps
Step 1: Paul has Opponents
The best entry into this new reading would be to consider the first thing I noted above: the diatribes. These signal that Paul is opposing a viewpoint, and possibly someone behind that viewpoint. That latter possibility is made more plausible by the following facts:
- Paul mentions rival teachers in 16:17–20: ‘I urge you, brothers and sisters, to watch out for those who cause divisions and put obstacles in your way that are contrary to the teaching you have learned. Keep away from them. For such people are not serving our Lord Christ, but their own appetites. By smooth talk and flattery they deceive the minds of naive people. Everyone has heard about your obedience, so I rejoice because of you; but I want you to be wise about what is good, and innocent about what is evil. The God of peace will soon crush Satan under your feet. The grace of our Lord Jesus be with you.’ Now, it is true that Paul only explicitly mentions these false teachers at the very end of the letter. However, this does not mean that it is not an important passage. On the contrary, the closing remarks of letters can contain some of the most important remarks, the things that the author wants the readers/hearers to really remember.
- Moreover, it has often been remarked that Romans 1–4, Galatians, and Philippians 3:2–4:3 make very similar arguments about justification, faith, circumcision, the Law, etc. However, this also makes it more plausible that Romans, just as Galatians and Philippians, was written in a (very) polemical context. As Louis Martyn writes, “It is in Paul’s struggle with the Teachers — themselves theologians who spoke at some length about rectification [= justification] — that we see him formulating his thought on rectification” (Galatians, 250). As with Galatians, this would provide a good contingent explanation of Paul’s argument in Romans. The common reasons provided for the writing of Romans (Paul wants to raise support for the collection for Jerusalem, and he wants to systematically expound his gospel for a new audience) simply fall short. The collection is a valid reason, but could not be the only reason to write such a long letter. Moreover, the whole category of ‘systematic’ is quite problematic. Arguably, some parts in Paul, especially Romans 5–8 and Ephesians 1–3, could be regarded as Paul’s ‘coherent’ views. However, if you read all parts of the letter in the same way — i.e., Rom 1–4, 5–8, 9–11 — , you end up with an incoherent Paul. They cannot all reflect pure Pauline exposition. It’s more likely that some parts — in this case, Rom 1–4 — reflects a polemical rhetorical strategy, attacking the ‘coherence’ of the gospel of opponents.
Step 2: Diatribes in 2:1–5 and 17–29
So, the diatribes are likely not generalized but have a particular person or group of people in mind. Now, if we take a look at the content of the first two diatribes in 2:1–5 and 2:17–29, we see some clear continuities:
1. The opponent is in both cases explicitly coded as a male individual,
2. who judges others for doing wrong (2:1–5) or teaches others to do good (2:17–29),
3. but is hypocritical, doing wrong himself.
So, it is a safe conclusion (which many interpreters make) that Paul is addressing the same person in these two diatribes. Of course, the first diatribe is more generic (“…oh human being…”) and the second more specific. However, this simply reflects Paul’s strategy of drawing in his readers.
Now we can expand the portrait of who Paul’s conversation partner precisely is in Romans 2:
4. He boasts about being a circumcised Jew and possessing the Torah (2:17–18, 20, 23, 27).
5. He boasts in God (2:17), supposedly being a sincere Jew and supposedly a Christian as well (which is why Paul writes this letter).
6. He teaches the Torah to the ‘foolish’ Gentiles (2:19–22), on which he looks down. (So, we can expect him to quote Torah.)
7. Moreover, he is likely learned, as he is a teacher, so we can also expect him to draw on other Jewish religious texts.
8. He judges and condemns Gentile sinners for doing wrong (2:1-3).
9. However, he does not ‘teach himself’, because he practices the same sins, and thus in judging Gentiles he condemns himself (2:1-5, 21–24).
We might call this person either ‘the Judger’ or ‘the Teacher’ — and Paul’s argument is, among other things, that he is a hypocrite.
Step 3: Diatribe in Romans 3:1–8
Then, in Romans 3:1–8, we find another diatribe. There is one party questioning the salvific value of circumcision and Jewishness (3:1), appealing to God’s faithfulness (3:3) and righteousness (3:5), and holding an almost libertarian ethical position (3:7–8a). The other party, giving the answers, hammers on the manifold privileges of Jews, especially the possession of the Torah (3:2), and God’s impartial judgment of the world (3:4, 6), and he condemns certain people (3:8b).
Now, which one is Paul, and which one is ‘the Teacher’? I hope you get the idea: the answering party. This confirms points 4 (Jewishness and circumcision), 6 (quoting Torah; 3:4 [Ps 51:4]) and 8 (judgmental language), and we can add the following two characteristics to the profile of the Teacher:
10. He is theologically committed to God’s impartial, retributive judgment of the world (3:4, 6).
11. He probably criticized Paul’s teaching for being ethically libertarian (3:7-8).
Step 4: Rereading 1:18–32
Now, if we go back in our text to Romans 1:18–32, we can ask the same question (that has maybe never been truly asked): whose profile does it fit, Paul’s or the Teacher’s? It’s clear that it fits the Teacher better than Paul. In fact, the hypocrite ‘judging’ activity mentioned in 2:1–5 is now seen to refer to the preceding passage, a classic Jewish denouncement of pagan idolatry and sexual immorality, with a clear judgmental undertone (point 6 above)— which becomes clear, for example, from the unparalleled repeated use of the third person plural and the equally unparalleled long list of sins. This identification also explains its similarities to the Wisdom of Solomon (see the top of the article), as the Teacher is probably a learned figure (point 7 above). Also, he is committed to God’s retributive judgment (1:32; point 10 above). Moreover, we can see now that the talk about natural revelation (which makes the pagans inexcusable) also pertains to the Teacher, which is relevant to the next passage.
But first, if it does not reflect Paul’s position, why does Paul write it to the Romans? Well, Paul lets his opponent do the opening salvo, so to say. He lets him do his talk, which could very well be the way the Teacher preached in the synagogue or in the churches. The Romans would have recognised this as non-Pauline, because (1) the style, tone, and content are clearly distinct from the rest of the letter, and (2) Paul would have explained such matters to the one bearing and reading the letter to the Roman church.
Another objection might be that Paul includes a doxology in the midst of this passage (1:25) — is this satirical!? Well, first of all, it suits the Teacher because of its reference to God as ‘Creator’ (τὸν κτίσαντα ton ktisanta); the substantive usage of κτίζω ktizō is unique to Paul. Secondly, it is not at all strange that the Teacher would also praise God since he is a sincere Jew or Jewish Christian (point 5 above).
Step 5: Rereading 2:6–11 and Further
Romans 2:6–11 and further also suits the Teacher very much: there is God’s judgment of the world on the basis of works, with a neat distinction between two types of people, ‘good’ and ‘bad’, which correspond, of course, to those who do the Torah and those who do not (2:13). Moreover, as noted above, this passage contains a citation from Scripture (2:6), Jewish hymnic material (2:7–10) and a Jewish aphorism (2:11), all of which can now be neatly explained by the profile of the Teacher.
So, in sum, what did the Teacher’s position look like? Probably something like the following:
God is going to judge the world impartially according to works on the basis of the Torah. Israel has the Torah and circumcision, so they will survive this judgment quite well. The pagans, however, who do not have and do Torah will be judged and condemned. Therefore, I have gone on a mission to the Gentiles, so that they will hear and do Torah, repent, and be circumcised. In this way, they can become part of the faithful people of Israel and escape the coming judgment.
Now, in 2:12–16, 25-29, we can perceive a subversion of Paul: if there really is something like natural revelation (as the Teacher argued in 1:18–21), then that must mean that there are some pagans who actually do God’s will apart from Torah because of their innate knowledge of good and evil (i.e., God’s will!), thus destabilising the whole system of the Teacher. His whole mission is in vain!
Moreover, we see Paul interjecting two phrases from his own gospel presentation:
- ‘God will judge the secrets of men according to my gospel through Christ Jesus’ (2:16). This is the only reference to Christ in all of 1:18–3:20 (!), and points to a whole other construal of the ‘gospel’, centered not around the Torah but around Christ — the one who died for the ungodly. This last phrase, if it were taken as the starting point, would drastically change the whole argument. So, it is a subversive addition of Paul himself, hinting at his own Christological gospel.
- Moreover, Paul says that pagans who do the Law are circumcised in the heart, ‘by the Spirit, not by the Letter’ (cf. 7:6), that is, without being physically circumcised and without having the Torah (2:27)! In the context of the parodic argument, it simply means that, in the Teacher’s own definition of Jew and Gentile, a Gentile doing the natural law qualifies as a Jew! But again, with his reference to the Spirit (again the only reference in 1:18–3:20!), Paul subverts the whole argument and hints at his own pneumatological gospel.
Step 6: Rereading 3:9–20
Finally, in Romans 3:9–20, we see that Paul’s rhetorical argument has worked brilliantly: the Teacher has to admit that God’s retributive judgment (in the Teacher’s account) does not take Jewish privilege into account, and he is silenced (3:8). Thus, the whole system of the Teacher, centered around Torah and circumcision, has come crashing down. In Romans 1:18–3:8, Paul has set up his rhetorical opponent and trapped him in his own system.
Paul then finishes off with a catena of texts establishing the fact that both Jews and Gentiles are under the power of Sin (3:9, which points to Paul’s own formulation of the gospel). The conclusion: the only thing the Law seems to be good for is bringing ‘knowledge of sin’ (3:20; cf. 7:7). Instead of silencing the pagans, it silences the boastful mouth of the Teacher himself (3:19). Simply put, the Law does not deliver, and cannot ‘deliver’.
Only then does Paul proceed to his own ‘apocalyptic’ gospel (3:21–26; cf. 1:16–17, 5:1 etc.), centred around God’s liberating justice in Christ. Here ‘justification’ proceeds from God’s unconditional love (5:5, 8; 8:28, 35, 39), regardless of man’s merit (and in fact regardless of the whole category of merit!), freeing humanity from the power of Sin (6:7).
‘But God demonstrates his own love for us in this: While we were still sinners, Christ died for us’ (5:8).
‘We know that our old self was crucified with him so that the body ruled by the power of Sin might be done away with, that we should no longer be slaves to the power of Sin — because anyone who has died with Christ has been justified, that is, liberated from the power of Sin’ (6:6–7, own translation).
‘Who then is the one who condemns? [cf. 2:16] Not Christ Jesus! He is the who died for you — more than that, who was raised to life —who is at the right hand of God and is also at this very moment interceding for us’ (8:34, own translation).
 Richard N. Longenecker, The Epistle to the Romans, New International Greek Testament Commentary (Eerdmans 2016).
 There, Paul references Psalm 14:1–3 (perhaps also 53:1–3; Ecclesiastes 7:20); Psalm 5:9; Psalm 140:3; Psalm 10:7 LXX; Isaiah 59:7–8 (perhaps also Proverbs 1:16), and Psalm 36:1.
 See the following list:
 See Campbell, Deliverance, parts 1–2, for his critique of ‘Justification Theory’, and part 3 for his critique of its reading of Romans 1–4, followed by his own (re-)reading in part 4, and his (re-)reading of other core passages as from Galatians in part 5.