What is Jeremias 31:34 affirming?

New blog on the kid: What is Jeremias 31:34 affirming? · HGL's F.B. writings: Fake Patristics

Some Protestants use this as saying that there will be no need for a Magisterium.

Let's look at the verse with previous verse:

But this shall be the covenant that I will make with the house of Israel, after those days, saith the Lord: I will give my law in their bowels, and I will write it in their heart: and I 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 all shall know me from the least of them even to the greatest, saith the Lord: for I will forgive their iniquity, and I will remember their sin no more
[Jeremias 31:33-34]

Now, certainly each man, even each child (and not just each Apostle) who is forgiven will know God and know what to do.

But by contrast with what?

Does it say "and priests shall teach no more the rest"? No, it says:

And they shall teach no more every man his neighbour, and every man his brother, saying: Know the Lord:

In other words, what ceases is a discipline of mutual correction. We are not dealing with a condemnation of the magisterium but of things like Holiness Churches and Islam, and before both obviously the OT Judaism and its quasi-continuation today. One man, not a priest, is saying to the other "know the Lord!" and then that other man, also not a priest tells the first man "know the Lord!" ... that's what is ceasing. When a Catholic is exposed to a climate of intense "fraternal correction" he has not chosen, he notices this kind of attitude as non-Catholic. And sure, in the New Testament, there is no continuous need for it, there is more like a free initiative within God's law.
/Hans Georg Lundahl

PS, this is pretty important for how we interpret certain words in the Sermon on the Mount.

And when you fast, be not as the hypocrites, sad. For they disfigure their faces, that they may appear unto men to fast. Amen I say to you, they have received their reward.
[Matthew 6:16]

Our Lord is not saying: teach nothing of the utility of fasting. Our Lord is not saying: don't let anyone know if people fast on a certain day in your Church.

He is saying, basically, "tell people it's a fast day, if it is, but don't tell them you are keeping it" ... which also implies, don't ask the other guy if he's keeping it.

That's why a certain fake quote from St. Ignatius of Antioch is NOT a valid exposition of this Bible word, or at least not the main one. It actually is not even one of them, check Catena Aurea for Matthew 6./HGL