26 - Chapter 18 The Believer's Rule: The Seventh Objection

And the law is written on a believer’s heart in the new covenant, written by the Spirit in regeneration. The terms and promises of the new covenant, prophesied in Jeremiah 31:31-34, and set out in Hebrews 8:6-13 and 10:16-17, are these:
Behold, the days are coming, says the LORD, when 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 lead them out of the land of Egypt, my covenant which they broke, though I was a husband to them, says the LORD. But this is the covenant that I will make with the house of Israel after those days, says the LORD: I will put my law in their minds, and write it on their hearts; and I will be their God, and they shall be my people. No more shall every man teach his neighbour, and every man his brother, saying: ‘Know the LORD’, for they all shall know me, from the least of them to the greatest of them, says the LORD. For I will forgive their iniquity, and their sin I will remember no more.
How should we interpret and apply such prophecies? What are the general principles? Specifically, of what time was Jeremiah speaking? To whom does this prophecy apply? And to what law does it refer?