So what about Jeremiah 31:31-34? It's really heartbreaking that people use this scripture to disprove true Torah keeping, when in fact, it's saying just the opposite. This may also be insightful to you.
Let's take a look:
Jeremiah 31:31 Behold, the days come, saith YHWH, that I will make a new covenant with the house of Israel, and with the house of Judah:
I want to stop here. This verse is very important. Sadly, the only words that are noticed by people in this verse are usually "new covenant". That's all people see, and then some assume this automatically connotes a different Torah where we don't have to keep it the "old way". But there is something very important in this verse. There are two parties mentioned here: the house of Judah and the house of Israel (ten northern tribes). Notice how both divided houses are distinguished here from eachother, as will be seen as significant later. This also rebukes any doctrine that "gentiles" as a separate entity from Israel as Yahweh's people are part of this covenant. Let us not add to the the Word when the Word says no such thing. Those from the nations/gentiles can become a part of this covenant through Messiah, but as such, they are considered Israel.
Jeremiah 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 YHWH:
What is this "not according to the covenant..." here? Many people only notice these words in this scripture too and assume it means that he doesn't require Torah obedience anymore. As we will see, this has nothing to do with changing his laws or standard of conduct. This has to do with the method Torah will be given this time. They were given on stone (and thus outside of the heart), through Moses (who broke the Torah) from Mt Sinai in the wilderness. He's not going to do that this time. Torah is an aspect of the covenant, not the entire covenant itself. Continuing:
Jeremiah 31:33 But this shall be the covenant that I will make with the house of Israel; After those days, saith YHWH, I will put my Torah in their inward parts, and write it in their hearts; and will be their God, and they shall be my people.
Once again, it is sad that most people look at "I will put my law in their inward parts and write it in their hearts", and then automatically think "see! that means that we keep only the moral laws now because the Spirit tells us what to do! it's not about rules and regulations!"
They ignore the rest of the verse, which is equally important, and they also prove that they need to read the rest of the scripture. They look at it from and unlearned, non-Hebraic, biased viewpoint. Notice he only mentions the house of Israel when he says he will put his Torah within them. Why does he do this, and why does he not include Judah? And why does he say he "will be their God, and they shall be my people"? Is this just a random statement? According to a lot of Christendom today, it very much is. He says this for absolutely no reason. It's just a nice little vain addition to this verse.
But as we will explicity prove, there is a reason only the house of Israel is mentioned in this verse, and there is a reason he says he "will be their God, and they shall be my people". This covenant was made to redeem all Israel (both houses) from division and all former sin (not to change Torah) and to bring both houses together in unity, which is what he is saying in the next verse:
Jeremiah 31:34 And they shall teach no more every man his neighbour, and every man his brother, saying, Know YHWH: for they shall all know me, from the least of them unto the greatest of them, saith YHWH: for I will forgive their iniquity, and I will remember their sin no more.
Both houses will no longer be divided having to teach one another as brothers and neighbors (Judah will not have to teach Israel the Torah and to know Yahweh for example, and Israel will not have to teach Judah about knowing Yahweh through Messiah) because both redeemed houses will know Yahweh and his Torah. He will forgive all iniquity (Torah-less-ness) and all sin and forget it (grace).
But back to Jeremiah 31:33; what is that saying? Let's take a look at Hosea, the prophet to the northern tribes. This will clear everything up:
Hosea 1:9 Then said Elohim, Call his name Loammi: for ye are not my people, and I will not be your God.
Hosea 1:10 Yet the number of the children of Israel shall be as the sand of the sea, which cannot be measured nor numbered; and it shall come to pass, that in the place where it was said unto them, Ye are not my people, there it shall be said unto them, Ye are the sons of the living God.
Hosea 1:11 Then shall the children of Judah and the children of Israel be gathered together, and appoint themselves One Head, and they shall come up out of the land: for great shall be the day of Jezreel.
Now you're probably like, "What the hey?". Although I'd advise you to read the chapter, I will give you a briefing on what's going on.
Yahweh through Hosea is declaring the curses and idolatry of Ephraim Israel (ten northern tribes, or the house of Israel). He tells him to take a wife of "whoredoms" (symbolizing the sin of the house Israel). He is using this to typify the curses of Israel through Hosea and his wife's children (who represent the children of the house Israel as opposed to Judah)
His first child with this wife (who's name was "Gomer") was a boy Yahweh commanded to be called Yizre-El, or "Jezreel", as it reads in the KJV. Yizre-El means "El will sow". El will sow what? The children of Israel scattered out in all nations. This is touched on in my "Gentiles of the NT" thread, so we won't get into the scattering part now and how Yahweh promised to sow the scattered seed of Israel.
Anyway, with the birth and naming of this child, Yahweh cursed the house of Israel with the cessation of their kingdom (Hosea 1:4-5).
The second child Hosea had by Gomer was a girl Yahweh commanded to be named Lo-ruchamah, which means "no mercy". He said he would not have mercy on the children of Israel but would have mercy on the house of Judah (Hosea 1:6-7). This let's us know that the house of Judah and the house of Israel are not the same, and are not interchangeable terms in this context. Here is a curse of no mercy upon the house of Israel for their Torah-less-ness.
Hosea's third child was commanded to be named Lo-Ami, meaning "not my people". He tells us this in the verses above that I posted, saying that the children of the house of Israel are as the sand of the sea, and that one day, in the land where it was said "you are not my people" by Yahweh, it would be said to them "you are the children of the living God".
Messiah at his first advent declared the reversal of these curses starting at the beginning of Matthew 5 as the fulfillment of this prophecy. The last verse, Hosea 1:11, brings Jeremiah 31:31-34 to light. This covenant was made (the NT reveals to us it was put into effect by the blood of Messiah) to bring both divided and scattered houses of Israel and Judah together and allows Yahweh to be their husand again despite the curses from their Torah-less-ness.
This is why Yahweh distinguishes the house of Israel from Judah in Jeremiah 31:33 and says what he said. He makes it clear that through this new covenant of redemption and restoration, he once again becomes their God and they his people. He had to write the Torah on their heart so they could do them, unlike before which is the reason they were cursed. Judah needs Messiah. He has Torah and even foolishly thinks it will save him and that he can reject Messiah because of it.
Jeremiah 31:31-34 has absolutely nothing to do with changing laws or only requiring the "moral laws" of Torah. Ezekiel makes it clear what this means:
Ezekiel 36:16 Moreover the word of YHWH came unto me, saying,
Ezekiel 36:17 Son of man, when the house of Israel dwelt in their own land, they defiled it by their own way and by their doings: their way was before me as the uncleanness of a removed woman.
Ezekiel 36:18 Wherefore I poured my fury upon them for the blood that they had shed upon the land, and for their idols wherewith they had polluted it:
Ezekiel 36:19 And I scattered them among the heathen, and they were dispersed through the countries: according to their way and according to their doings I judged them.
Ezekiel 36:20 And when they entered unto the heathen, whither they went, they profaned my holy name, when they said to them, These are the people of YHWH, and are gone forth out of his land.
Ezekiel 36:21 But I had pity for mine holy name, which the house of Israel had profaned among the heathen, whither they went.
Ezekiel 36:22 Therefore say unto the house of Israel, Thus saith the Master YHWH; I do not this for your sakes, O house of Israel, but for mine holy name's sake, which ye have profaned among the heathen, whither ye went.
Ezekiel 36:23 And I will sanctify my great name, which was profaned among the heathen, which ye have profaned in the midst of them; and the heathen shall know that I am YHWH, saith the Master YHWH, when I shall be sanctified in you before their eyes.
Ezekiel 36:24 For I will take you from among the heathen, and gather you out of all countries, and will bring you into your own land.
Ezekiel 36:25 Then will I sprinkle clean water upon you, and ye shall be clean: from all your filthiness, and from all your idols, will I cleanse you.
Ezekiel 36:26 A new heart also will I give you, and a new spirit will I put within you: and I will take away the stony heart out of your flesh, and I will give you an heart of flesh.
Ezekiel 36:27 And I will put my spirit within you, and cause you to walk in my statutes, and ye shall keep my judgments, and do them.
Ezekiel 36:28 And ye shall dwell in the land that I gave to your fathers; and ye shall be my people, and I will be your God.
This is the reason Yahweh gives us a new heart and why he writes his Torah on our heart by the Spirit: so we can perform his Torah. Just for the "rules and regulations" sake? No. So we can just do what Yahweh said with a joyful, pure, obedient, repentant heart. And this is how loving Yahweh with all heart/soul/mind/strength and loving our neighbor as ourselves is the basis of all the Torah and Prophets.
This is how love fulfills the Torah. Not that we redefine what right and wrong is based of our manmade concept of "morale". Torah was always supposed to be on the heart. This is not a new concept. Yahweh said it through Moses long before Jeremiah or the New Testament was written:
Deuteronomy 6:6 And these words, which I command thee this day, shall be in thine heart:
Deuteronomy 10:16 Circumcise therefore the foreskin of your heart, and be no more stiffnecked.
Deuteronomy 30:10 If thou shalt hearken unto the voice of YHWH thy God, to keep his commandments and his statutes which are written in this book of the Torah, and if thou turn unto YHWH thy God with all thine heart, and with all thy soul.
Deuteronomy 30:11 For this commandment which I command thee this day, it is not hidden from thee, neither is it far off.
Deuteronomy 30:12 It is not in heaven, that thou shouldest say, Who shall go up for us to heaven, and bring it unto us, that we may hear it, and do it?
Deuteronomy 30:13 Neither is it beyond the sea, that thou shouldest say, Who shall go over the sea for us, and bring it unto us, that we may hear it, and do it?
Deuteronomy 30:14 But the word is very nigh unto thee, in thy mouth, and in thy heart, that thou mayest do it.
This is the Spirit put in us by and through Messiah Yahshua. He is the "Word" that is "nigh" to us. Paul makes this clear in Romans 10:4-13.