LA's thesis is wrong and you're wrong about he/she being right, however...you're right about GOD's intentions for the twelve and Israel taking the gospel of the Kingdom to the nations, for that was according to prophecy. However, Israel didn't get on board so GOD's next move was to bring on the tribulation and His wrath leading up to the notable Day of the LORD, or either do what He did do which was to incorporate Paul with pure grace to proclaim the gospel of the grace of GOD and the cross as good news to the nations which, as Israel was then reckoned with the nations, meant that individual Jews would be saved on the same basis as individual gentiles.
The elect of Israel did get on board, the unbelievers were rejected and the Gentile believers added into the elect of Israel.
Joh 1:11 He came unto his own, and his own received him not.
Joh 1:12
But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name:
Rom 11:1 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.
Rom 11:2 God hath not cast away his people which he foreknew. Wot ye not what the scripture saith of Elias? how he maketh intercession to God against Israel, saying,
Rom 11:3 Lord, they have killed thy prophets, and digged down thine altars; and I am left alone, and they seek my life.
Rom 11:4 But what saith the answer of God unto him? I have reserved to myself seven thousand men, who have not bowed the knee to the image of Baal.
Rom 11:5 Even so then at this present time also there is a remnant according to the election of grace.
Rom 11:6 And if by grace, then is it no more of works: otherwise grace is no more grace. But if it be of works, then is it no more grace: otherwise work is no more work.
Rom 11:7 What then? Israel hath not obtained that which he seeketh for; but
the election hath obtained it, and the rest were blinded
Act 4:1 And as they spake unto the people, the priests, and the captain of the temple, and the Sadducees, came upon them,
Act 4:2 Being grieved that they taught the people, and preached through Jesus the resurrection from the dead.
Act 4:3 And they laid hands on them, and put them in hold unto the next day: for it was now eventide.
Act 4:4
Howbeit many of them which heard the word believed; and the number of the men was about five thousand.
Eph 2:11 Wherefore remember, that ye being in time past Gentiles in the flesh, who are called Uncircumcision by that which is called the Circumcision in the flesh made by hands;
Eph 2:12
That at that time ye were without Christ, being aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world:
Eph 2:13 But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ. Eph 2:14 For he is our peace, who hath made both one, and hath broken down the middle wall of partition between us;
Eph 2:15 Having abolished in his flesh the enmity, even the law of commandments contained in ordinances; for to make in himself of twain one new man, so making peace;
Rom 9:6 Not as though the word of God hath taken none effect. For they are not all Israel, which are of Israel:
Rom 9:7 Neither, because they are the seed of Abraham, are they all children: but, In Isaac shall thy seed be called.
Rom 9:8 That is, They which are the children of the flesh, these are not the children of God:
but the children of the promise are counted for the seed.
Gal 3:26 For ye are all the children of God by faith in Christ Jesus.
Gal 3:27 For as many of you as have been baptized into Christ have put on Christ.
Gal 3:28 There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus.
Gal 3:29
And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise.
LA