“righteousness.” In this context, “righteousness” is doing what is right to God and others (see commentary on Matt. 5:6).
“We have been in sin for a long time, and will we be saved?” This phrase is very unclear in the Hebrew text. Many scholars say the Hebrew text has been corrupted and there have been a number of emendations to the text that have been suggested to try to make the Hebrew more understandable, but the emendations are without textual support. Furthermore, the last sentence can be a statement or a question. The REV follows what some scholars believe is the most reasonable possibility that the text is saying (see John Oswalt, The New International Commentary on the Old Testament: The Book of Isaiah, Chapters 40-66).
One thing that seems clear from the context and scope of Isaiah is that the people are caught up in sin and cannot be saved on their own, but need God’s merciful intervention to be saved.