They are Israelites. Theirs is the adoption as sons, the glory, the covenants, the giving of the law, the worship, the promises.
In context
2there is great sorrow in me, and a pain in my heart that never lets up. 3I could wish myself accursed and cut off from the Christ for the sake of my brothers, my own flesh and blood. 4They are Israelites. Theirs is the adoption as sons, the glory, the covenants, the giving of the law, the worship, the promises. 5Theirs are the patriarchs, and from them, as to the flesh, came the Christ, who is over all, God blessed forever. Amen. 6It is not that God’s word has fallen through. Not everyone descended from Israel is Israel,
