Peter Leithart, in his The Four, posed the question, “What is Jeremiah’s point about the ark in Jeremiah 3:16? How does that fit with what we have learned about the ‘last days’?”
And when you have multiplied and been fruitful in the land, in those days, declares the Lord, they shall no more say, “The ark of the covenant of the Lord.” It shall not come to mind or be remembered or missed; it shall not be made again.
It seems to tie in with the new covenant promised in Jeremiah 31: 31-33
“Behold, the days are coming, declares the Lord, when I will make a new covenant with the house of Israel and the house of Judah, not like the covenant that I made with their fathers on the day when I took them by the hand to bring them out of the land of Egypt, my covenant that they broke, though I was their husband, declares the Lord. For this is the covenant that I will make with the house of Israel after those days, declares the Lord: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people…”
I will put my law within them, and I will write it on their hearts. Where was the law hidden before and on what was it written? It was hidden in the ark which was locked away in the Holy of Holies and written on tablets of stone. But now, under this new covenant God puts the law in the minds of His people and writes it on their hearts. As Ezekiel says, “And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh.” So, the new covenant makes the people of God a living ark, in the same way that we are being made into a living temple for the Spirit. Also locked up in the ark were the manna (bread from heaven, cf. John 6) and Aaron’s staff that budded (among other things, the resurrection from the dead).
What makes this more interesting (for me anyway) is what the ark was in the old covenant. The ark was the throne of God , where He sat enthroned on the cherubim (2 Samuel 6:2, cf 1 Sam 4-7:2). It didn’t just sit in the temple, though. It was a fiery chariot-throne, as Ezekiel sees in Ezekiel 1, carried around by the four cherubim. So, if the covenant people of God are now the new ark (and we are in the new covenant), God is no longer being carried around by the cherubim but by the church. We are now His fiery chariot-throne, the God-bearer in the world.