James D. G. Dunn and N. T. Wright agree that “the righteousness of God” in Paul’s usage really means “the covenant faithfulness of God.” But there is a perfectly good word for “faithfulness” in Greek (πιστότης) that Paul could have used. Paul does not use this exact word, but he comes close. He speaks of “the faithfulness of God” (ἡ πίστις τοῦ θεοῦ) (Rom 3:3). Three times he says that “God is faithful” (πιστὸς ὁ θεός) (1 Cor 1:9; 10:13; 2 Cor 1:18), and on other occasions he uses the adjective πιστός in reference to God or Christ (1 Thess 5:24; 2 Thess 3:3; 2 Tim 2:13).
In addition, Paul uses a variety phrases and idioms to affirm that God keeps his promises, but none of them involves the use of “righteousness” terminology: “… so that the promise (ἡ ἐπαγγελία) will be guaranteed (βέβαιος) to all the seed” (Rom 4:16); “With respect to the promise (ἡ ἐπαγγελία) of God he did not waver in unbelief … being fully assured that what God had promised (ἐπήγγελται), he was able also to perform” (Rom 4:20-21); “It is not as though the word of God has failed” (Rom 9:6); “The gifts and the calling of God are irrevocable” (Rom 11:29); “For I say that Christ has become a servant to the circumcision on behalf of the truth of God (ἀλήθεια θεοῦ) to confirm (εἰς τὸ βεβαιῶσαι = ‘in order to fulfill’ [BDAG]) the promises (αἱ ἐπαγγελίαι) given to the fathers” (Rom 15:8); “For as many as are the promises (ἐπαγγελίαι) of God, in him they are yes … Now he who establishes (ὁ βεβαιῶν) us with you in Christ and has anointed us is God” (2 Cor 1:20-21); “the Law, which came 430 years later, does not invalidate a covenant previously ratified by God, so as to nullify the promise (ἡ ἐπαγγελία)” (Gal 3:17).
Paul frequently uses the noun or verb for “promise” in the contexts where he wants to affirm the faithfulness of God. Yet the words for “promise” are strikingly absent from the contexts where Paul speaks of “the righteousness of God.” This suggests that the translation “the covenant faithfulness of God” is incorrect.
-Lee Irons, original article HERE