And being Jewish certainly DOES matter even after Christ's coming. At least, being a true Jew does. No one who isn't part of Israel, true Israel, will be saved. The thing is, that has nothing to do with ethnic origin. It has everything to do with having faith like Abraham, and specifically faith in the promised JEWISH messiah.

If you are a Christian, you are part of true Israel, a Jew by faith, regardless of your ethnicity.

Meanwhile, if you are a Jew by ethnicity, but have no faith in Jesus, you are no Jew at all. You are cut off from the covenant people of God. Most who profess to be Jews are no Jews at all in the eyes of God.