The author of Hebrews (assumed to be Paul), was in chapter 8 quoting much of what was written by the prophets in Jeremiah 31 and Ezekiel 37. While there are many prophetic aspects to these verses about the rejoining of Ephraim and Judah back together as the one set-apart nation, these verses are quick to make the point within context of reading the complete chapters.
“And they shall by no means teach each one his neighbour, and each one his brother, saying, ‘Know יהוה,’ because they all shall know Me, from the least of them to the greatest of them.
~ (Hebrews 8:11)
“And no longer shall they teach, each one his neighbour, and each one his brother, saying, ‘Know יהוה,’ for they shall all know Me, from the least of them to the greatest of them,” declares יהוה. “For I shall forgive their crookedness, and remember their sin no more.” ~ (Jeremiah 31:34)
So, according to Jeremiah and Paul, one of the prerequisites to the establishment of the New Covenant is that we will no longer preach the gospel to the nations. Why? – Because “they shall all know me”. This doesn’t happen until after Yeshua’s (Jesus) second coming and the elect are gathered together in the New Jerusalem for the millennial reign.
From this prerequisite alone we can conclude the New Covenant isn’t established yet. Therefore, the Law of Moses and the Mosaic Covenant have not “vanished away”.
While I think this is contradicted by other Gospels it does raise the issue. If you don't know Jesus then the Mosaic Covenant applies. If you don't know the Mosaic Covenant and you don't believe in Jesus, say you are a Hindu. Do either Covenants apply to you?
Tim