Is interracial marriage sinful?

A central tenet of kinism seems to be that God wants people to keep themselves within strict ethnic groupings. Were this so, one would expect the Lord to have mentioned this some place in the Scriptures. Not only is there no such mention, but the Bible explicitly teaches that ethnic and tribal identity are utterly beside the point when it comes to one’s relationship to God. What kinist scriptural arguments I have found are classic examples of eisegesis: that is, reading an existing belief into a Bible verse which does not in fact teach that doctrine. I won’t quote Romans 4:1–12 here, but you will note that faith in Christ’s work makes one righteous before God and a child of Abraham. Paul argues very strenuously that Jews (“the circumcised”) are not truly descendants of Abraham in God’s eyes unless they share his faith. If the Lord Christ has no place for gene pool considerations within his church, why would he be concerned with them among the nations which exist only to provide members for the church?