For he himself is our peace, who has made us both one and has broken down in his flesh the dividing wall of hostility by abolishing the law of commandments expressed in ordinances, that he might create in himself one new man in place of the two, so making peace, and might reconcile us both to God in one body through the cross, thereby killing the hostility.
Gentiles and Jews, having spent generations of separation, can be reconciled - through Jesus. Looking at the cross suddenly changes everything about taking offense and giving forgiveness in our relationships.
How can the law-keeping, ceremonially clean, religious Jew be reconciled to the law-breaking, unclean, sinning Gentile? How can the church-going, clean-cut, moralistic "good" person be reconciled to the church-hating, scruffy, "godless" person? Only through Jesus. It's in his flesh (v14), in himself (v15), through the cross (v16). It's now one body, one man in place of two. The old categories have been broken down. The distinctions of Jew, Gentile, Christian, Muslim, good, bad, rich, poor, generous, tight, intelligent or stupid are no longer relevant. Language, colour, culture and class don't matter. There are only two categories. With Jesus or without him. In Christ or far off. In Him, we can be reconciled to God and each other. Away from him, the divisions remain because the division between us and God remains.