The question expressed in the title was answered generations ago by the founders of the many cults (denominations) that comprise professing Christendom.  Their parishioners, assuming that they were being taught the Truth, and not willing to “prove all things” concerning spiritual matters (1 Thes. 5:21), embraced the popular notion that Gentiles had replaced Israelites in the heart of God.  Because of this error, the church was believed to be a Gentile institution in which all beliefs, customs and practices of God’s former chosen people had been relegated to the dustbin of religious history.  After all, did not God “divorce” the Israelites (Jer. 3:8), including the Jews (tribes of Judah, Benjamin & Levi)?  Indeed He did divorce both the northern tribes (called Israel) and the southern tribes (Judahites–“Jews”).  He also sent both groups into slavery before scattering them throughout the world where most of them, now numbering in the hundreds of millions, remain to this day.  Because they lost their Israelite identities (language, religion, customs, etc.) they came to believe themselves to be Gentiles and continue to be known as Gentiles to this day.  Read Who and Where is Israel Today?  Key word–Today.  Chapter 3 of Jeremiah’s book speaks of the Lord’s divorcement of His chosen people.  Chapters 9,13,18 & 49 tell of His world-wide scattering of “the sheep of My flock” among the Gentiles.  Human reasoning–the end result of a lack of “fine print” study, says that the Israelites were permanently cast to the spiritual wayside and that the Gentiles replaced them as God’s chosen people.  This theory is called “Replacement Theology.”  Read the series by that name using “Replacement” as the key word.

The Catholic/Protestant Church is the most dangerous institution on earth relative to man’s eternity.  Replacement Theology is one of her most deadly weapons in that it blinds salvation seekers to the fact that God’s true church is an Israelite institution.  To prove this we will turn to Jesus Christ and the mission statements recorded in the Holy Scriptures relative to His earthly ministry.

In Matthew 1:20,21 we find Joseph being told by an angel that the child Mary was carrying would “save HIS PEOPLE from their sins.”  In 2:6 we find the Lord proclaiming that the “Governor” He would send to earth would rule “My people ISRAEL.”  In Matthew 10:6 we find Jesus sending His apostles, not to the Samaritans, not to the Gentiles, but to “… the lost sheep of the house of ISRAEL.”  Then in 15:24 He proclaimed that He had been sent to earth only for the “… lost sheep of the house of ISRAEL.”

In Luke 1:16,17 an angel tells the father of John the Baptist that his son would go before the “Him” (the Messiah) to help in His ministry by which He would turn many ISRAELITES back to the Lord their God.  In Luke 2:25-32 we read about a priest named Simeon whom God had told that he would see the Lord’s Christ.  Upon seeing baby Jesus he thanked the Lord that He had allowed him to see His Messiah who would bring glory to “Your people ISRAEL.”

In John 1:49 Jesus has just told a man named Nathaniel something He had no way of knowing outside of divine revelation.  Nathaniel said Him: “Rabbi, You are the Son of God; You are the King of ISRAEL.”  Jesus did not correct him.  In Acts 1:6,7 Christ’s disciples ask Him when He would restore the earthly kingdom to ISRAEL.  Jesus did not correct them.  As a man He could not answer their question.  Only God, He told them, knew when He would restore the kingdom to ISRAEL.

In Jeremiah 31:31-34 we find the Lord saying that one day He would make a NEW COVENANT WITH THE HOUSE OF ISRAEL AND WITH THE HOUSE OF JUDAH (the Jews)–all Israelites.  (All Jews are Israelites but not all Israelites are Jews).  Upon Israel’s arrival at Mt. Sinai, God (Who later came to earth as Jesus of Nazareth) had verbally declared to them His Ten Commandment Covenant (Law).  Later, He made an additional covenant with Israel relative to His weekly 7th day (Saturday) Sabbath (the 4th commandment) which would be the sign that they were His people (Jer. 31:12-16).  That has not changed.  This is the same weekly Sabbath that God calls “… My holy day” (Isa. 58:13,14).  Here God dictates what His people would do on His Holy Sabbath Day.  His people would not do their own pleasure, speak their own words and go their own ways on His Holy Day.  They would call His Sabbath a delight, holy unto the Lord and honorable.  In so doing they would delight themselves in Him.

Upon giving the Israelites His Law verbally, some of the people rejected it and entered into a sex orgy (Exo. 32:25), for which He killed about 3000 men.   They had broken the covenant God had made with them (Exo. 31:32).  Because of this He had given them the sacrificial law that involved blood sacrifice.  This is called “the law that was added” to the Ten Commandment Law because of the sins of the people (Gal. 3:19).  This is the law that Jesus nullified at the Last Supper.  This was the “handwriting of ordinances” that was nailed to His cross.

God vowed to make a better covenant with Israel in the future, saying: “Behold, the days come when I will make a new covenant with the house of Israel and with the house of Judah ….  This will be the covenant that I will make with them: I will put My Law in their inward parts and write it in their hearts, and (then) I will be their God and they will be My people.”  At that point all Israel would know Him and, because the Law would be in their hearts (minds), they would not need to be taught God’s ways.

The Law that God said He would write on the hearts of His people is the Law that the Apostle Paul said was “holy, just and good” (Rom. 7:12).  It is the Law that defines sin and righteousness–sin if one breaks it and righteousness if one obeys it (1 Jn. 3:4).  L.J.