More on Mystery Israel:
In Romans 11 Paul write of God’s eternal purpose in Christ Jesus Eph 3:11. He states that it has always been God’s eternal purpose to save his elect Israel by calling each of his elect from among Jew and Gentile by Christ our Deliverer. Rom 11: 25-27 is a sort of parenthesis in the midst of his gentle reroof concerning God’s eternal purpose for his elect Israel. He declared that the mystery of God, God’s eternal purpose is to save all his elect from among the Jew and the Gentiles, as foretold by Jesus words Jn 10:16. That Israel shall be saved Isa 45:17 is a Gospel Promise, that included Gentiles Eph 3:6
6 That the Gentiles should be fellowheirs, and of the same body, and partakers of his promise in Christ by the gospel:
And when God has fulfilled his purpose, by calling all his elect of jews and gentiles from the Gentile nations. “And so” and after this manner—"all God’s elect Israel shall be saved.” Rom 11:26
Elect Gentiles are fellowheirs with the Old Test heirs as Per Heb 11:8-10
8 By faith Abraham, when he was called to go out into a place which he should after receive for an inheritance, obeyed; and he went out, not knowing whither he went.
9 By faith he sojourned in the land of promise, as in a strange country, dwelling in tabernacles with Isaac and Jacob, the heirs with him of the same promise:
10 For he looked for a city which hath foundations, whose builder and maker is God.
Gentiles are Heirs with the Fathers in the Eternal Kingdom of Inheritance Matt 8:8-12
8 The centurion answered and said, Lord, I am not worthy that thou shouldest come under my roof: but speak the word only, and my servant shall be healed.
9 For I am a man under authority, having soldiers under me: and I say to this man, Go, and he goeth; and to another, Come, and he cometh; and to my servant, Do this, and he doeth it.
10 When Jesus heard it, he marvelled, and said to them that followed, Verily I say unto you, I have not found so great faith, no, not in Israel.
11 And I say unto you, That many shall come from the east and west, and shall sit down with Abraham, and Isaac, and Jacob, in the kingdom of heaven.
12 But the children of the kingdom shall be cast out into outer darkness: there shall be weeping and gnashing of teeth. 8