"Behold, the days come, saith the LORD, that I will make a new covenant with the house of Israel, and with the house of Judah:
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:
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." Jeremiah 31: 31-33
Jeremiah 31: 31-33 is talking about the remaking of Old Covenant Israel and referring to that remaking as being a New Covenant. II Kings 21: 13 says that God is to "turn Jerusalem upside down," Isaiah 29: 16 points to Jeremiah 18: 4-5, which is the parable of the lump of clay - which Paul refers to in Romans 9: 21 - and Jeremiah 18: 4-5 says God will remake Israel.
In Jeremiah 18: 1-6 Old Covenant Israel is seen to be a lump of clay on a potter's wheel. In Jeremiah 18: 4 the vessel God made out of the lump is marred in the hand of the potter, and "so he made it again another vessel, as seemed good to the potter to make it." God then says in Jeremiah 18: "O house of Israel, cannot I do with you as this potter?"
In the metaphor of the potter first making a pot that was marred and then remaking the same lump of clay as another pot, he, as God, saw as being good, a potter can actually do this. The potter takes the flawed pot off the potter's wheel, lays the wet lump of clay down on a table, mixes in dry clay, kneads it with his hands a while, and then puts the same lump of clay back on his potter's wheel and makes a better pot out of it.
Is the New Covenant of Jeremiah 31: 31-33 just a renewed form of the Mosaic Law? It may be that dispensationalists would want to think so, since they want to honor Old Covenant Israel and to become surrogates for those they see as being of Old Covenant Israel.
God promises in Isaiah 55: 3 that "Incline your ear, and come unto me: hear, and your soul shall live; and I will make an everlasting covenant with you, even the sure mercies of David." Since the Old Covenant was done away with (II Corinthians 3: 7, 3: 11, Hebrews 10: 9), then the covenant which is to be everlasting is the New Covenant. Isaiah 61: 8, supported by Jeremiah 32: 40, Jeremiah 50: 5,Ezekiel 16: 60 and Ezekiel 37: 26.
Ezekiel 11: 19 promises to give the house of Israel one heart and a new spirit and take the stony heart out of Old Covenant Israel.
Ezekiel 18: 31 says for Israel to make for themselves new heart and a new spirit. "For why will ye die, O house of Israel?"
Hebrews 13: 20-21 talks about The "... blood of the everlasting covenant, make you perfect in every good work to do his will, working in you that which is wellpleasing in his sight" The New Covenant is everlasting, not a temporary "dispensation," which is to give way to another dispensation of law for the people of the physical bloodline in some future time.
Hebrews 7: 22 says "By so much was Jesus made a surety of a better testament." And Hebrews 8: 6 says "But now hath he obtained a more excellent ministry, by how much also he is the mediator of a better covenant, which was established upon better promises."
"And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance." Hebrews 9: 15
Since Jesus Christ himself is the mediator of the New Covenant, the spiritual light which shines into the hearts of the believers in the New Covenant is greater than the light shining in the Old Covenant.
"And said unto me, Thou art my servant, O Israel, in whom I will be glorified....... And he said, It is a light thing that thou shouldest be my servant to raise up the tribes of Jacob, and to restore the preserved of Israel: I will also give thee for a light to the Gentiles, that thou mayest be my salvation unto the end of the earth." Isaiah 49: 3-7
"Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life." John 8: 12
"Ye are the light of the world. A city that is set on an hill cannot be hid.
15. Neither do men light a candle, and put it under a bushel, but on a candlestick; and it giveth light unto all that are in the house. Matthew 5: 14-15
Israel, with Christ in it, is the light to the world. Without Christ, Israel is not the light to the world.
Old Covenant Israel was remade into the spiritual house in I Peter 2: 5, and so the New Covenant is not the renewal of the Old Covenant, but a remaking and transformation of the Old Covenant.
"If so be ye have tasted that the Lord is gracious.
4.To whom coming, as unto a living stone, disallowed indeed of men, but chosen of God, and precious,
5.Ye also, as lively stones, are built up a spiritual house, an holy priesthood, to offer up spiritual sacrifices, acceptable to God by Jesus Christ." I Peter 2: 3-5
"Ye" in I Peter 2: 3-5 are those of the elect who are under the New Covenant. Who else could "ye" be?
Those of the New Covenant who are the elect are a spiritual house, implying that they are a spiritual house because they are in Christ and he in them, as a fulfillment of some Old Testament prophecies, which may not have said in an explicit way that in Christ, under the New Covenant, Christ was to create a spiritual house.
And under the New Covenant those not of the chosen people physical bloodline were brought into the people of God as equals. The elect of God are not chosen under the New Covenant according to their physical bloodline, but are chosen according to their faith as Galatians 3 says though in ways that is a little bit subtle.
"Behold, I have given him for a witness to the people, a leader and commander to the people.
5.Behold, thou shalt call a nation that thou knowest not, and nations that knew not thee shall run unto thee because of the LORD thy God, and for the Holy One of Israel; for he hath glorified thee." Isaiah 55: 4-5
"And I will sow her unto me in the earth; and I will have mercy upon her that had not obtained mercy; and I will say to them which were not my people, Thou art my people; and they shall say, Thou art my God." Hosea 2: 23