The Israel of God (Galatians 6: 16) did not arise out of the multitude of Old Covenant Israel. It arose out of the remnant of Israel seen in Romans 11: 1-5. In Romans 9: 27 Paul quotes Isaiah 10: 20-22, "And it shall come to pass in that day, that the remnant of Israel, and such as are escaped of the house of Jacob, shall no more again stay upon him that smote them; but shall stay upon the LORD, the Holy One of Israel, in truth. 21. The remnant shall return, even the remnant of Jacob, unto the mighty God.
22. For though thy people Israel be as the sand of the sea, yet a remnant of them shall return: the consumption decreed shall overflow with righteousness."
The remnant of Israel included the Apostles.
But dispensationalism took over much of the evangelical denominations of the Capital C Church, and it, which is Christian Zionism after 1948, teaches that the multitude of Old Covenant Israel remain the chosen people because of the bloodline, which Galatians 3: 3, 16,26- 29 says in a way too subtle for the Christian Zionists to understand, that the physical bloodline from Abraham became one seed, Jesus Christ, and "...if ye be Christ's, then ye are Abraham's seed, and heirs according to the promise."
There is also a remnant of Israel in the New Covenant time. The 144,000 of Revelation 7 and Revelation 14 is a remnant, and the remnant is seen in end time prophecy in Revelation 12: 15-17.
But Christian Zionism does not acknowledge there being a remnant of Israel in the New Covenant timeline.
"From the time of Christ’s rejection by Israel until the time when God deals specifically with Israel again in the seventieth week it is not possible to refer to a remnant of the nation Israel." Things to Come: A Study in Biblical Eschatology, 1965, by J. Dwight Pentecost
In Christian Zionism Israel has become the flesh and blood nation called Israel in the Middle East.
"And the dragon was wroth with the woman, and went to make war with the remnant of her seed, which keep the commandments of God, and have the testimony of Jesus Christ." Revelation 12: 17 King James Version
Many of the recent New Testament translations have changed the Greek word λοιπων, Strong's number 3062, from remnant in the 1526 Tyndale New Testament, the 1599 Geneva Bible and the 1611 King Jams Version to a different word.
The New Revised Standard has "Then the dragon was angry with the woman, and went off to make war on the rest of her children, those who keep the commandments of God and hold the testimony of Jesus."
The New International says "Then the dragon was enraged at the woman and went off to wage war against the rest of her offspring—those who keep God’s commands and hold fast their testimony about Jesus."
The New King James Version has for Revelation 12: 17: "And the dragon was enraged with the woman, and he went to make war with the rest of her offspring, who keep the commandments of God and have the testimony of Jesus Christ."
Young's Literal Translation says "and the dragon was angry against the woman, and went away to make war with the rest of her seed, those keeping the commands of God, and having the testimony of Jesus Christ."
All four of the recent English Bible translations shown above translate Strong's number 3062, loipoy, as rest, saying the rest of her seed, or the rest of her offspring.
Using rest instead of the word remnant, which the three older New Testaments use, changes the doctrine. The "rest of her offspring" does not clearly connect to the remnant of Israel in Isaiah 10, 20-22 in Romans 9: 27 or in Romans 11: 1-5. The "rest' of her seed could refer to something different than the remnant of Israel in scripture.
Here are the Oxford Dictionaries on the meanings of remnant and the rest: Remnant: "Origin: Middle English: contraction of obsolete remenant, from Old French, from remenoir, remanoir 'remain'. "A small remaining quantity of something," "Christian Theology: A small minority of people who will remain faithful to God and so be saved (in allusion to biblical prophecies concerning Israel)." Rest: Origin: Late Middle English: from Old French reste (noun), rester (verb), from Latin restare 'remain," "The remaining part of something," "The remaining people or things; the others," "and (all) the rest (of it)."
Remnant and rest can overlap to some extent in their meanings, in the sense that a remnant is the rest of something which remains, while the larger part does not remain. But translating loipoy as the rest of something tends to lead the meaning away from the Biblical concept of a few people who remain faithful to God, to the doctrines of Christ, while the multitude goes off into false doctrines and practices.
So, there is a change of doctrine, though subtle or ambiguous, from the first three English New Testaments based upon the Textus Receptus, for Revelation 12: 17 on the meaning of loipoy, to the recent English translations, almost all from the Westcott-Hort Greek and not the Textus Receptus.
The principle of the remnant says that when the multitude goes off into false doctrines and false practices God raises up a remnant to began again his work of redemption.
The cutting off of the multitude in Romans 11: 17-20 who were following the false doctrines as leaven of the Pharisees (Matthew 16: 6, Luke 12: 1), and beginning a new Israel in the remnant of Romans 11: 5 was a major transformation of Israel from the Old Covenant to the New Covenant. In that remaking, the Old Covenant, which operated in the physical, was done away with (II Corinthians 3: 11, Hebrews 10: 9),and a New Covenant, which operated in the spiritual, was created in and by Christ. That which was physical under the Old Covenant - physical bloodline from Abraham, physical circumcision, a physical temple building, physical animal sacrifice, etc - was all done away with as shadows (Hebrews 10: 1, Colossians 2: 17). That which is in the spiritual - in Christ Jesus - became the substance.
My little children, of whom I travail in birth again until Christ be formed in you." Galatians 4: 19 "Let this mind be in you, which was also in Christ Jesus:" Philippians 2: 5
"Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new." II Corinthians 5: 17
"And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God." Romans 12: 2
But false doctrines keep Christ from being formed in you, so that you remain in the spiritual condition of the natural man of I Corinthians 2; 14, who does not discern the things of the Spirit.
The remnant of Israel began that transformation in Christ brought about by the Holy Spirit in the First Century. The multitude of Old Covenant Israel rejected Christ and did not want their religion turned upside down (Acts 17: 6). They were cut off.
