Romans 9:4 "Who are Israelites; to whom pertaineth the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises".
What you may hear at your church is that God's people rejected Him and so all can now be adopted in to the church. This is based on false theology. Did you know that the Greek word for adoption is not found in the new testament? Scripture says what it means and is correct. There is no need to spiritualize this verse. What many churches are guilty of is changing the meaning or focus of a verse by spiritualizing that verse because it does not fit their theology or what they think they see in the world.
Romans 11:1-2a "I say then, Hath God cast away his people? God forbid. For I also am an Israelite, of the seed of Abraham, of the tribe of Benjamin. God hath not cast away his people which he foreknew."
Let's take the view that scripture is correct. Yahweh God did not fail with His plan of salvation. Scripture tells us that there were many thousands of Israelites who were immersed and became Christians. Where are the children of those thousands of Israelites today? They are not found among today's Jews. The scripture defines its own words. Sheep are several times defined by scripture as Israelites. If one says that non-Israelites are sheep then they are spiritualizing scripture.
John 10:27 "My sheep hear my voice, and I know them, and they follow me".
As mentioned the Greek word for adoption is not found in the new testament. The word translated adoption in most English translations means "placement of sons". That is placement of those who are already sons. It was a coming of age event.
One must make a decision to believe Paul's writing or ignore him altogether. Paul said the adoption or placement of sons belongs to Israel. It does not belong to anyone else. Notice also the rest of the verse. Some have correctly figured that the Law is only for Israel as is plainly stated in Psalms 147:20. The covenants also belong to Israel. That includes the new covenant. It was made only with true physical Israel as is shown in Jeremiah 31 and Hebrews 8. Hebrews makes it clear it was a very physical, not spiritualized people who were lead by the hand.
Hebrews 8:8-10 "For finding fault with them, he saith, Behold, the days come, saith the Lord, when I will make a new covenant with the house of Israel and with the house of Judah: Not according to the covenant that I made with their fathers in the day when I took them by the hand to lead them out of the land of Egypt; because they continued not in my covenant, and I regarded them not, saith the Lord. For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to me a people". See also Jeremiah 31:31-33
If you find another verse that you think contradicts Hebrews 8, then it does not mean what you think it means. Yahweh God no where says that the covenant is made with any people other than those descended from Jacob. What about the people who have mostly been Christians for almost the last two thousand years? The modern day Jews are not Israelites. Read the scripture with that in mind and realize that true Israel has been mostly hearing and obeying Christ for almost 2000 years. Scripture will then make much more sense.
This is the original intent of this article. Let it speak, let the scripture speak. Perhaps what we think we know is not correct. True Israel is not found among today's Jews as they do admit in some of their writings. True Israel is found where all the prophecy and promises point. Israel is found in the people who, if they have had any religion at all, have claimed Christ as their redeemer and Lord for almost 2000 years.