Did you not read these verses?:
"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: 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: 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. And they shall teach no more every man his neighbour, and every man his brother, saying, Know the LORD: for they shall all know me, from the least of them unto the greatest of them, saith the LORD: for I will forgive their iniquity, and I will remember their sin no more" (Jer.31:31-34).
In this passage we can see that the "fathers" of both the house of Israel and the house of Judah are the physical descendants of Abraham, Isaac and Jacob. Their "fathers" broke the LORD's covenant and it was the physical descendants of Jacob who did that.
So these verses are not referring to all of mankind, as you imagine, but instead are strictly in regard to the physical seed of Abraham, Isaac and Jacob.
Besides that there has never been a time when all of the physical descendants of Jacob knew the LORD and had their sins forgiven. Therefore, the fulfillment of this prophecy remains in the future.
And anyone with spiritual insight knows that is a fact!
You have little.
The verses are showing the weakness of the old covenant calling out through the flesh, compared with the salvation of the Spirit.
Hebrews shows it is a done deal.
Heb 8:1
Now of the things which we have spoken this is the sum: We have such an high priest, who is set on the right hand of the throne of the Majesty in the heavens;
Heb 8:2 A minister of the sanctuary, and of the true tabernacle, which the Lord pitched, and not man.
Heb 8:3 For every high priest is ordained to offer gifts and sacrifices: wherefore it is of necessity that this man have somewhat also to offer.
Heb 8:4 For if he were on earth, he should not be a priest, seeing that there are priests that offer gifts according to the law:
Heb 8:5 Who serve unto the example and shadow of heavenly things, as Moses was admonished of God when he was about to make the tabernacle: for, See, saith he, that thou make all things according to the pattern shewed to thee in the mount.
Heb 8:6 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.
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, 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.
Heb 8:13 In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away.
LA