After 2021, a year in which I did much study on the doctrine of imputed righteousness, I have compiled a list of verses on the subject. I will begin with the list, along with my conclusion on whether the verse is absolutely certain (XX), certain (X), probable (O), or possible (*) as regards the imputed righteousness of Christ and then explain my reasoning. They are listed in order of approximate likelihood. Many of these texts are intrinsically linked textually (just use the treasury of scripture knowledge to check), especially 1-5 and 8.
Romans 5:17-19 (XX)
Isaiah 53:11 (XX)
2 Corinthians 5:21 (XX)
1 Corinthians 1:30 (XX)
Philippians 3:9 (XX)
Matthew 3:15 (X)
Galatians 4:4 (X)
Jeremiah 23:6 (and 33:16) (X)
Galatians 2:17 (X)
Romans 8:3-4 (O)
Romans 10:4 (O)
2 Peter 1:1 (O)
1 John 2:1 (O)
Galatians 2:20 (*)
1 John 3:7 (*)
Romans 5:17-19 is certainly speaking of the righteousness of Christ being imputed to those in Him (see Schreiner, Moo). I have a post on the section here.
Isaiah 53:11 is certain. See my comments in the above post as well as Motyer's Isaiah commentary. If 45:24 is translated a certain way, it may be seen as parallel to 53:11 (see Motyer on 45:24) and would be a close parallel to Jeremiah 23:6/33:16.
2 Corinthians 5:21 also follows as certain. See Murray J. Harris' 2 Corinthians commentary in NIGTC, Carson, and Vickers "Blood and Righteousness". See also John Chrysostom.
1 Corinthians 1:30 also lands in certain. See Beale's comments in "A New Testament Biblical Theology", Anthony Thiselton's 1 Corinthians NIGTC, and Schreiner "Faith Alone".
I have listed Jeremiah 23:6 (and 33:16) as certain. This may seem strange to some, but the logic and thought in the verse are the same as 1 Cor. 1:30 and Phil. 3:9, which is why I have covered it between these two. A biblical-theology of righteousness will show that the verse speaks of the Messiah being His people's righteousness. It is hard to take the verse any other way as it certainly does not say that the Lord will make His people righteous, but is their righteousness. See also Chou "I Saw The Lord" pg. 124, who correlates Daniel 9:24 with Jeremiah 23:6 (given Daniel has Jeremiah in mind in 9:2) and Isaiah 53:11 (cf. Dan. 9:26 with Is. 53:8). Thus the servant justifies His people by being their righteousness. This passage also connects with Zech. 3:8, 10, speaking of the Edenic conditions ushered in by the Branch. This relates to the dominion Adam was supposed to have, implying then that just as the Messiah was to become His people's righteousness, this was what Adam was originally supposed to do, bringing in Sabbath rest on the basis of his obedience. See 1 Kings 4:25, which uses the same phrase (under their fig tree), clearly painting Solomon as a New Adam all throughout (3:9, 4:20, 24, 25-26, 29, 33, 5:4-5) and Micah 4:4 (see also Gen. 49:11) again applying it to the Messiah as the new and perfect Adam. This is fulfilled in John 1:48-49 (under the fig tree…Son of God…King of Israel), which portrays Jesus as the New Adam who will have dominion, bring in the New Creation of inaugurated Sabbath rest, and be His people's righteousness upon which that rest will been ushered in.
Philippians 3:9 I have also listed as certain. See Carson, Beale in his NTBT, Schreiner's comments in "Faith Alone", and "The Doctrine on Which the Church Stands or Falls" (hereafter DCSF), which should be consulted for all the verses listed here. Note it is also this verse that best connects to Romans 3-4, identifying the righteousness that is imputed as Christ's.
Matthew 3:15 is again certain. See Beale in NTBT, R. T. France's NICNT commentary on Matthew, and Brandon Crowe's "The Last Adam". See also Cyril of Alexandria.
Romans 10:4 is listed as probable. See Vickers' "Blood and Righteousness" pg. 215
Galatians 4:4 is probable. See Owen's comments at the end here. More exegetical work must be done to show passive obedience here implies active obedience (or active obedience is primarily in view as opposed to passive) in order to make this certain. EDIT: Richard Longnecker's comments in WBC: The second participal clause at the end of v. 4, "born under the law," lays stress on another factor involved in the representative work of "the Son." For it was not just that Christ came as "the Man" but also that he came as "the Jew" under obligation to God's Torah, so fulfilling the requirements of the law in his life (cf. Matt 5:17-18) and bearing the law's curse in death (cf. Gal 3:13; Phil 2:8). . . the early church spoke of Christ not only as being truly human and possessing a representative quality ("the Man") but also as "born under the law" to offer a perfect obedience to God the Father on behalf of those under the law".
Though I would argue the focus is on Christ being under the moral law (as republished in the CoR commanding Christ to obey and fulfill it as well as take our curse) rather than the Mosaic Law specifically (so Doug Moo, Gal., pg. 267), so we have a focus on Christ the man, not necessarily Christ the Jew, though His obedience to the Mosaic Law is obviously included as a Jew derivatively from the moral law. Though me and Moo could be wrong here, yet it still doesn't really matter, for Christ's obedience to the Mosaic Law is contained in the Covenant of Redemption by which He would obey it and would also die for all both under the Mosaic Law specifically and those under the moral law which is itself contained in the Mosaic Law. Longnecker also posits a Logos-Christology ("God sent forth His Son") implying the pre-existence of the Son. I would add to this that we also have an Adamic-Christology ("His Son") as is often the case when we see a Logos-Christology (see for example G.K. Beale's comments on Colossians 1:15-20 in Beale and Carson, where he suggests both) as they are intrinsically related, Adam being an image and type of Christ, the eternal Son; and Christ sharing both natures. This Adam-Christology adds support for seeing positive obedience to the law in Galatians 4:4. F. F. Bruce also briefly notes this.
This was good enough in my mind to move this verse to certain.
I have listed Romans 8:3-4 as only probable. The best defense is Doug Moo's in Romans (which Andy Naselli follows in DCSF; he has since changed his mind. Simon Gathercole, John Chrysostom, and Peter Martyr Vermigli also take this) and I really want him to be correct oh so badly, but sadly I don't think he is. Schreiner in Romans, pg. 400-401 shows Moo's arguments are not decisive, but the death blow for me was Beale's comments in NTBT pg. 254. The parallel to Ezekiel, which certainly speaks of believers' lived-out obedience after regeneration is too strong. I really want to list this as at least probable, but after seeing the Ezekiel parallel in Beale's NTBT, I can't hold that this can possibly be the correct interpretation. Nevertheless, I still hope for a good defense of Moo's position to come out somewhere that satisfactorily addresses Beale's argument as well. It's such a strong argument for imputed righteousness if Moo is correct, but it's just massively unlikely that in a verse where 2 competing interpretations are both viable and strong, one of which sees this as lived-out regenerate obedience to the Law in the New Covenant, and Paul directly alludes to an O.T. passage that speaks about exactly that, for the alternate interpretation to be correct.
Edit: I asked Dr. Jason DeRouchie about this and here's what he had to say: I agree with Beale that there is an allusion to Ezek 36, but Beale fails to account for the distinction between plural “statutes” (Ezek 36; Rom 2) and singular “statute” (Rom 5, 8). I think Paul sees Christ’s imputed righteousness as providing a context for the Spirit to empower the keeping of God’s statutes. Rom 8:4 includes both ideas: the singular “statute in you” refers to imputed righteous and those who “walk according to the Spirit” to what Ezekiel envisioned. Christ’s singular statute keeping occurs in both Rom 5:18–19 and 8:4, whereas the Christians’ keeping of statutes occurs in Rom 2:26 and is echoed at the end of Rom 8:4 and reasserted in 13:8.
This interpretation becomes highly probable if Galatians 4:4 is closely parallel (see Doug Moo, Galatians, pg. 264; Swain "The Trinity and the Bible", pg. 93, footnote 24).
Because, however, I keep going back and forth on how to interpret this verse, and good scholars disagree, I have decided to keep this verse at "probable".
As for me personally, I have since become convinced of the interpretation offered by Colin Kruse and thus would not use this verse to defend imputed righteousness. Kruse and Augustine have convinced me.
I have listed Galatians 2:17 as certain. This is a verse that I have often overlooked in my reading. See esp. Schreiner on Galatians, Justification and Variegated Nomism: The Paradoxes of Paul pg. 348, and Doug Moo on Galatians.
2 Peter 1:1 I have listed as probable. See DCSF, pg. 464. I think this has a chance to even be certain, but much more work must be done and I haven't looked into it too much. Schreiner says that ""The term “righteousness” elsewhere in 2 Peter, it is pointed out, refers to his justice and fairness (2 Pet 2:5, 21; 3:13). The phrase “through the righteousness of our God and Savior Jesus Christ” modifies the participle “received.” The emphasis on God’s grace and gift in the context (cf. 1:3–4) suggests that fairness is not the most natural meaning in context. The gift of faith given by God is not understood in the NT to be “fair” but entirely of grace. Thus, God’s righteousness here does not denote his fairness but his saving righteousness. This accords with the OT, where God’s righteousness is parallel to his “salvation” (Pss 22:31; 31:1; 35:24, 28; 40:10; Isa 42:6; 45:8, 13; 51:5–8; Mic 6:5; 7:9)"". But the thing is that God's saving righteousness is the same thing that Paul is talking about in Romans 3-4, informed by the same O.T. verses, and it is this righteousness, which Paul says in Romans 3-4 is imputed to us. So it seems very natural to take 2 Peter 1 as saying that the saving righteousness imputed to us is Christ's (especially given Phillippians 3:9 or even just the fact that "faith" and "righteousness" appear together), but I don't know why modern commentators don't do this. John Calvin and John Gill seem correct IMO to take this as imputed righteousness (if Gill is correct this would also provide a basis for the active/passive justification distinction because it says that our faith comes by the righteousness of Christ. The imputation of righteousness logically precedes the faith which grasps it).
I have listed 1 John 2:1 as probable. The logic of the verse seems to be that if we sin, our sins may be covered because of our advocate/representative in Heaven, Christ, who is righteous. It seems close to the words of Bunyan and parallel to the thought of 1 Corinthians 1:30 and 2 Corinthians 5:21.
Galatians 2:20 is possible, see Carson's comments again. I don't know of anyone else who holds to this besides Carson. Needs more work.
1 John 3:7 is listed as possible. Some old writers (Gill, Henry) thought it spoke of imputed righteousness. I think it's quite unlikely and no modern commentary takes it.
A final honorable mention that I don't know how to rank is Revelation 19:8, see Beale's comments in his Revelation commentary pg. 943. His comments in other places serve as my hermeneutical paradigm for interpreting verses such as Psalm 24:4 and Matthew 5:20 in that they refer fully and meritoriously to Christ and analogically and necessarily of believers, both flowing from our union with Him for justification and sanctification and might be used here. More work must be done to connect "granted to her" as implying imputed righteousness and it must be connected to a biblical-theology of clothing/garments that must prove they represent imputed righteousness as opposed to, say, regeneration or intrinsic righteousness/good deeds arising from it or the ability to do them. This is very interesting to me and I want to write a paper on a biblical theology of clothing/garments and see if it truly is related to imputed righteousness one day and if so, figure out whether it's explicitly connected to Christ (Rom. 13:14 possibly does). See also "Justification and Variegated Nomism" pg. 499.
See also Acts 3:13, "The God of Abraham, Isaac, and Jacob, the God of our fathers, has glorified His Servant Jesus", listed as an allusion to Is. 53:11. The idea is that Christ was justified by His resurrection ("glorified") and thus we are justified ("He will justify the many") by virtue of our union with the resurrected Christ. The final verdict to be declared at the eschaton has been brought forth in Christ's resurrection (cf. Beale NTBT pg. 522).
By no means do I intend this to be all the arguments set forth for Christ's imputed righteousness; rather, I have chosen to list only the verses that most explicitly/implicitly teach the imputed obedience/righteousness of Christ to those whom He represents. The best way to make the argument, IMO, is the biblical-theological pattern of Adamic-covenant heads ("sons of God") having their obedience to the law counted to those they represent (Adam, Abraham, Davidic King) or simply being under a covenant of works (Adam, Abraham, Israel, Davidic King). I have made such an argument in my post on the Covenant of Works and in the notes on my post on Psalm 2. Indeed, I think the best argument for Christ's imputed righteousness period is actually Romans 4:25, right after the first 5 verses listed here. I explained the logic of this verse in my post on Psalm 2; put simply, the verse implies that eternal life (in this case resurrection life) is obtained through obedience to God's Law, to his Torah on which he meditates day and night, by "doing this and living" (cf. my post on the Covenant of Works, especially the pages of Abner Chou's book), so by raising Christ from the dead, the decree of "just" is pronounced upon Christ, and therefore all that are in Him. Were Christ not raised, He would still be under the judicial/penal condemnation of death that He suffered to take the curse for our sins, and so we would be only condemned in Him. Being raised, He receives the legal verdict of justification for the completion of His work of obedience unto death and therefore we are justified in Him. You literally cannot ask for a better verse, as this has all the elements of the Reformed doctrine of justification via the imputed righteousness of Christ. All sacrificial imagery even implies this as the lambs slaughtered under the OT had to be sinless and without spot or blemish so that the one identified with it would become sinless and without spot before God in order to be in the right before Him. Imputed righteousness is implied even in the OT sacrifices. cf. 2 Cor. 5:21. To this numerous other arguments could be added. We have the blessed man of Ps. 1 who obtains abundant life by his meditation on the law (I've cited multiple sources for this on this site before but to add one more see Hamilton "Typology" pg. 357). We have the man who ascends the Mountain of Yahweh through his clean hands and pure heart. The imputation of the active obedience of Christ is assumed throughout the whole canon of Scripture.
I want to do more work to prove that Phil. 2:8-9 ought to be seen as meritorious on Christ's part, but granting parallels to John 10:18, Rom. 5:19, Isa. 52:13, and Isa. 53:12, as the ESV Study Bible does (and I'd add in John 17:3-4), would be a great start (see my post on Romans 5:12-19 for Isaiah) in putting us in the same conceptual thought space as the Covenant of Redemtpion whereby Christ is given a charge by the Father to fulfill the righteousness of the law in obedience unto death. If it is asked whether Christ's obedience is meritorious or a gracious reward (similar to how the verse is being used in an analogy to believers who will be graciously rewarded with glorification through their obedience, cf. 2:12), it can be replied that though there is analogy (obedience is rewarded), there is an important distinction, granting the parallels we have spoken of, which speak of Christ meeting the demands of the righteousness of the law (cf. Rom. 5:19, Is. 53:11, Psalm verses by which he extends life by meditating on the law) securing the legal right to eternal life for Himself and those He represents; the only way for something to be meritorious in relation to God is if He obliges Himself to reward one on the legal basis of obedience (such arrangement we call a "covenant"), and this Christ accomplished for Himself and for us, having received a charge from His Father (John 10:18, Rom. 4:25, 5:19, 2 Cor. 5:21). In short, His death accomplished the earning of the legal right to our justification, whereas, our obedience is merely an instrumental means to the end of a gracious reward.
Silva is helpful here:
It may help us to see our way out of this dilemma if we consider, first, that the Christ-hymn, though it certainly describes Christ's sacrificial work, does not have as its primary object setting forth the vicarious character of his obedience. In other words, we need not fear that an emphasis on the gracious character of God's act in exalting Jesus subverts the principle of Christ's meritorious obedience on behalf of his people.
Second, the Christ-hymn implies a correspondence between Christ's experience and the believer's sanctification leading to glorification, not between Christ's exaltation and the sinner's justification. Surely, believers are exhorted to persevere in their Christian race so that they may receive the prize (Phil. 3:13-14), but we need not for that reason fear
that the notion of reward conflicts with Paul's doctrine of justification (Rom. 4:5, "to the one who does not work ...").
See too, Romans 16:20, which I'd mark down as certain (on my more confident days).