“…God’s purpose in calling Abraham was to bless the whole world, to call out a people from Gentiles as well as Jews. This purpose has now been accomplished through the faithfulness of the Messiah, and all who believe in him constitute this fulfilled-family-of-Abraham. The law was given to keep ethnic Israel, so to speak, on track. But it could never be the means by which the ultimate promised family was demarcated, partly because it kept the two intended parts of the family separate, and partly because it served to demonstrate, by the fact that it was impossible to keep perfectly, that Jews, like the rest of the human race, were sinful. The Messiah’s death deals with…this double problem.”
— N. T. Wright in Justification
What Wright is saying is that the central problem for Gentiles is not only: (a) that we have sinned and death has come to us, as it has to all the human race; but furthermore, (b) that we are outside God’s covenant people and that the Torah (Law) serves as a barrier because (1) it distinguishes between Jew and Gentile; and, (2) because it showed how Israel– who was supposed to carry God’s blessing to all nations– had fallen short.
To make full sense of this, you can’t read “law” in Paul’s letters simply as “rules” or “moral code”, but specifically as “Mosaic Law” or “Torah”.
Jesus both dealt with Israel’s sin– and all human sin!– and, as the faithful Israelite, fulfilled Israel’s mission to carry blessing to all peoples. In short, sin has been paid for AND fractured humanity has been healed (in the sense that for those who are in Christ there is now no distinguishing between Jew and Gentile).