Mat_15:24 But he answered and said, I am not sent but unto the lost sheep of the house of Israel.
Jer 31:31 Behold, the days come, saith the LORD, that I will make a new (renewed) covenant with the house of Israel, and with the house of Judah:
Jer 31:32 Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the LORD:
Jer 31:33 But this shall be the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people.
The giving of the covenant at Mount Sinai was written on stone tablets, and the Hebrews and the sojourners were willing to say "All that the Lord says we will do". It was a marriage contract. But there hearts were hard and they were unable to keep their end of the contract. The result was God divorced the House of Israel. And a better covenant was to be put in place. This time with the Helper and Comforter to put the Law in their inward parts and write it in their hearts so that they can remarry God.
Oh but wait! God's own law forbids remarrying the adulterous wife - ie. The House of Israel (lost sheep).
Dueteronomy 24:1-4 1. When a man hath taken a wife, and married her, and it come to pass that she find no favour in his eyes, because he hath found some uncleanness in her: then let him write her a bill of divorcement, and give it in her hand, and send her out of his house. 2 And when she is departed out of his house, she may go and be another man's wife. 3 And if the latter husband hate her, and write her a bill of divorcement, and giveth it in her hand, and sendeth her out of his house; or if the latter husband die, which took her to be his wife; 4 Her former husband, which sent her away, may not take her again to be his wife, after that she is defiled; for that is abomination before the LORD: and thou shalt not cause the land to sin, which the LORD thy God giveth thee for an inheritance.
The prophet Jeremiah knew of God's plan to take the House of Israel back and remarry, but he exclaimed that he could not understand how God can break his own law.
Jer 3:1 They say, If a man put away his wife, and she go from him, and become another man's, shall he return unto her again? shall not that land be greatly polluted? but thou hast played the harlot with many lovers; yet return again to me, saith the LORD.
However, the apostle Paul figured out the mystery of the gospel.
Rom 7:1 Know ye not, brethren, (for I speak to them that know the law,) how that the law hath dominion over a man as long as he liveth?
Rom 7:2 For the woman which hath an husband is bound by the law to her husband so long as he liveth; but if the husband be dead, she is loosed from the law of her husband.
Rom 7:3 So then if, while her husband liveth, she be married to another man, she shall be called an adulteress: but if her husband be dead, she is free from that law; so that she is no adulteress, though she be married to another man.
Rom 7:4 Wherefore, my brethren, ye also are become dead to the law by the body of Christ; that ye should be married to another, even to him who is raised from the dead, that we should bring forth fruit unto God.
Mat_15:24 But he answered and said, I am not sent but unto the lost sheep of the house of Israel.
Jesus came as God in the flesh, so that He could die, be buried and resurrect so that the LOST SHEEP OF THE HOUSE OF ISRAEL CAN NOW REMARRY THE LORD because the law that applies to marriage and divorce has been made nullified.
Heb 8:7 For if that first covenant had been faultless, then should no place have been sought for the second.
Heb 8:8 For finding fault with them, (not the first covenant but with the people) he saith, Behold, the days come, saith the Lord, when I will make a new covenant with the house of Israel and with the house of Judah:
Heb 8:9 Not according to the covenant that I made with their fathers in the day when I took them by the hand to lead them out of the land of Egypt; because they continued not in my covenant, and I regarded them not, saith the Lord.
Heb 8:10 For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to me a people:
Heb 8:11 And they shall not teach every man his neighbour, and every man his brother, saying, Know the Lord: for all shall know me, from the least to the greatest.
Heb 8:12 For I will be merciful to their unrighteousness, and their sins and their iniquities will I remember no more.
I do not see Jesus coming to make a New Religion called the Church that does away with the covenant of marriage to the House of Israel and House of Judah. I do not see Jesus changing God's laws, but repeatedly says over and over that He does the Father's will.
I do see teachings in the New Testament of adoption and grafting and becoming part of the commonwealth of Israel.
In Revelation we can see the New Religion called Church do not keep the Lord's commandments, and the Jews do not have the faith of Jesus.
Rev_12:17 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.
Rev_14:12 Here is the patience of the saints: here are they that keep the commandments of God, and the faith of Jesus.
What does it take to be one of God's people?
Exo_31:13 Speak thou also unto the children of Israel, saying, Verily my sabbaths ye shall keep: for it is a sign between me and you throughout your generations; that ye may know that I am the LORD that doth sanctify you.
Eze_20:12 Moreover also I gave them my sabbaths, to be a sign between me and them, that they might know that I am the LORD that sanctify them.
Eze_20:20 And hallow my sabbaths; and they shall be a sign between me and you, that ye may know that I am the LORD your God.