The indicative was preferred in
UBS4 (and SBLGNT) on internal grounds: Paul is making a statement about the
result of righteousness through faith rather than urging his audience to make
peace with God. In addition, there is only one secure instance of εχωμεν elsewhere in the epistles (Rom.
15:4). Nevertheless, it may be noted that this verb is co-ordinated with the
subjunctive καυχωμεθα (‘let
us boast’) in the following verse, and there is a further subjunctive at the beginning
of the next sentence. A case can therefore also be made for εχωμεν, which is adopted in the THGNT.
Other instances of the same type of variation can be seen at Rom. 6:1, 14:19,
and 1 Cor. 15:49. (H. A. G. Houghton, A Textual Commentary on the Greek New
Testament: A Companion to the Sixth Edition of the United Bible Societies’
Greek New Testament [Stuttgart: Deutsche Bibelgesellschaft, 2025], 388-89)