That is Replacement Theology and not true. We we’re put on the shelf by GOD The Father after we as a people( although, there were about a million Messianic Jews in the first century) rejected Yeshua, but we never rejected by GOD and all of his promises towards Israel are still in place. the Jewish Messiah Yeshua will bring Israel back to GOD the Father.
Israel may presently be regathered as a nation by in large in unbelief; but the wonderful news is there is coming a day when "they will look upon Him whom they have pierced"; "mourn for Him as one mourns for his only son" and as a nation, the remnant that is left after 3 1/2 years of unprecedented, world-wide persecution ("the time of Jacob's trouble") will individually and collectively as a nation believe on the Lord Jesus Christ to the saving of their souls and thus "ALL ISRAEL WILL BE SAVED".
As a believing gentile, I thank God for the Jews and for Israel; ALL that I have in Christ I humbly owe to them! They alone were given "the oracles of God"; They alone are "the apple of God's eye"; as a nation, they alone are God's "chosen people" and most important of all; in His perfect humanity, my Savior is a Jew: "the seed of David"; "the Lion of Judah", the descendant of Abraham through whom "all the world will be blessed".
Along with the Apostle Paul; my prayer and burning heart's desire for Israel is that Israel may believe on Yeshua; their promised Messiah (Isaiah 53; Psalm 22), and be saved.
My beloved friend, if you are a Jew (or gentile) and you are reading this: God loves you. He loves you so much that He sent His sinless son into this sinful, lost and dying world; born of a virgin, born under the Law in order to fulfill the entire law so that He, the sinless, spotless "Lamb of God who takes away the sin of the world", would be sacrificed "outside the camp", crucified on a cruel cross; be cursed of God in order to shed His precious blood to make atonement for all of your sins and mine so that we may believe on the Lord Jesus Christ and be saved; delivered from the power and penalty of our sins; given eternal life and made sons and heirs of God through faith in Yeshua and His finished work on Calvary. Not only this; but God the Father demonstrated that He is completely satisfied with Yeshua's ONE, perfect, all sufficient, sacrifice by bodily, physically raising Yeshua from the dead on the third day, just as Yeshua had said He would!
"What must I do to be saved?" "Believe on the Lord Jesus Christ and you shall be saved". "For whosoever calls upon the name of the Lord SHALL BE SAVED"!