If you are not of Israel; you are not in covenant with YHWH.
(CLV) Hb 8:10
"For this is the covenant which I shall be covenanting with the house of Israel after those days," the Lord is saying: "Imparting My laws to their comprehension, On their hearts, also, shall I be inscribing them, And I shall be to them for a God, And they shall be to Me for a people.
If you are not of Israel Yahshua wasn't commissioned for you.
(CLV) Mt 15:24
Now He, [Yahshua] answering, said, "I was not commissioned except for the lost sheep of the house of Israel."
OH! OH! But WE'RE grafted IN! Grafted into what?
(CLV) Ro 11:17
Now if some of the boughs are broken out, yet you, being a wild olive, are grafted among them, and became joint participant of the root and fatness of the olive,
What is this olive tree?
(CLV) Jer 11:16
A flourishing olive tree, lovely with shapely fruit, Yahweh had called your name; But with the sound of a great din, He will ravage its leaves with fire, And its branches will be smashed.
(CLV) Jer 11:17
Yahweh of hosts Who planted you has decreed evil against you owing to the evil of the house of Israel and the house of Judah, which they have done for themselves to provoke Me to vexation by fuming incense to Baal.
If this and Jeremiah 31 were the only verses- then I would agree with you!
For the New covenant was made with the twelve tribes of Israel, to replace the old covenant that Israel could not keep.
However:
Romans 11:
11 I say then, Have they stumbled that they should fall? God forbid: but rather through their fall salvation is come unto the Gentiles, for to provoke them to jealousy.
12 Now if the fall of them be the riches of the world, and the diminishing of them the riches of the Gentiles; how much more their fulness?
13 For I speak to you Gentiles, inasmuch as I am the apostle of the Gentiles, I magnify mine office:
14 If by any means I may provoke to emulation them which are my flesh, and might save some of them.
15 For if the casting away of them be the reconciling of the world, what shall the receiving of them be, but life from the dead?
16 For if the firstfruit be holy, the lump is also holy: and if the root be holy, so are the branches.
17 And if some of the branches be broken off, and thou, being a wild olive tree, wert grafted in among them, and with them partakest of the root and fatness of the olive tree;
18 Boast not against the branches. But if thou boast, thou bearest not the root, but the root thee.
19 Thou wilt say then, The branches were broken off, that I might be grafted in.
20 Well; because of unbelief they were broken off, and thou standest by faith. Be not highminded, but fear:
21 For if God spared not the natural branches, take heed lest he also spare not thee.
22 Behold therefore the goodness and severity of God: on them which fell, severity; but toward thee, goodness, if thou continue in his goodness: otherwise thou also shalt be cut off.
23 And they also, if they abide not still in unbelief, shall be grafted in: for God is able to graft them in again.
24 For if thou wert cut out of the olive tree which is wild by nature, and wert grafted contrary to nature into a good olive tree: how much more shall these, which be the natural branches, be grafted into their own olive tree?
25 For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.
26 And so all Israel shall be saved: as it is written, There shall come out of Sion the Deliverer, and shall turn away ungodliness from Jacob:
27 For this is my covenant unto them, when I shall take away their sins.
28 As concerning the gospel, they are enemies for your sakes: but as touching the election, they are beloved for the father's sakes.
Ephesians 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;
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:
13 But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ.
14 For he is our peace, who hath made both one, and hath broken down the middle wall of partition between us;
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;
16 And that he might reconcile both unto God in one body by the cross, having slain the enmity thereby:
17 And came and preached peace to you which were afar off, and to them that were nigh.
18 For through him we both have access by one Spirit unto the Father.
19 Now therefore ye are no more strangers and foreigners, but
Under the old covenant gentiles were without hop. But now we are fellowheirs with Israel and partakers of the covenant through faith by8 grace.