And that the Gentiles might praise (ta de ethnē doxasai). Coordinate with bebaiōsai and eis to, to be repeated with ta ethnē, the accusative of general reference and ton theon the object of doxasai. Thus the Gentiles were called through the promise to the Jews in the covenant with Abraham (Rom 4:11., Rom 4:16.). Salvation is of the Jews. Paul proves his position by a chain of quotations from the O.T., the one in Rom 15:9 from Psa 18:50. For exomologeō, see note on Rom 14:11.
I will sing (psalō). Future active of psallō, for which verb see note on 1Co 14:15.