This verse has many renderings and translations. Under this one, it makes sense only if one has a God of flesh. Paul was addressing the Jews and having a God of flesh is totally foreign to their faith for thousands of years. The more correct rendering taking the context and the context of Jewish religion, this is the more correct translation:
5 Whose are the fathers, and of whom as concerning the flesh Christ came, who is over all, God blessed for ever. Amen. KJV
5 whose are the fathers, and from whom is the Christ according to the flesh, who is over all, God blessed forever. Amen. NASV
5 whose are the fathers, and of whom is Christ as concerning the flesh, who is over all, God blessed for ever. Amen. ASV
5 the Patriarchs are theirs; and from them, as far as his physical descent is concerned, came the Messiah, who is over all. Praised be ADONAI for ever! Amen. CJB
5 whose [are] the fathers; and of whom, as according to flesh, [is] the Christ, who is over all, God blessed for ever. Amen. DBY