When the Temple was built, “The inner sanctuary he [Solomon] prepared in the innermost part of the house, [the Debir] to set there the ark of the covenant of the LORD” (1Ki 6:19), “in the inner sanctuary of the house, in the most holy place, underneath the wings of the cherubim” (1Ki 8:6). Debir is from the same root as Davar, the Word. There is an important lesson here for our time. What makes man human is his word: human language is more than computer or animal language, human speech is more than the transmission of information or affect. But speech must have a foundation, because how can you force someone to believe what I tell you? What we must understand is that man can have a human word because at the beginning, God spoke to him. The divine word founded the human word.
The lid of the Ark of the Covenant is called the "mercy seat", from a Hebrew word meaning "to cover", with the metaphorical meaning "to atone for sins". On the Great Day of Atonement, the high priest sprinkled this lid with the blood of the victim offered for the sins of the people
(cf. Lev 16). The mercy seat, as has been said, is also the place of the mysterious presence of God. The blood of the sacrifice, in which all the sins of the Hebrews have been absorbed, is purified by 'touching' the deity, and the men represented by that blood are made pure. Moreover, through the process of the days leading up to Yom Kippur, the Jewish experience of divine mercy has a communal dimension.
Nebuchadnezzar conquered Jerusalem in 597 BC and took all the treasures of the temple and the royal palace. Then, in 587, he burned the temple and stripped it of all the precious objects used for worship (2 Kings 24-25; 2 Chr 36:10; Is 39:6). However, out of modesty, the Ark of the Covenant is not named among the looted objects: at the time of the destruction of the temple, obedient to a divine oracle, the prophet Jeremiah took the Ark of the Covenant and hid it in a cave (2Mac 2:4-8). Some rabbinic testimonies say that the Ark has disappeared and that it is destined to last until the future world [1]. God's covenant with Israel is eternal, which is why the Ark is incorruptible. It may even be in heaven if necessary (Rev 11:19).
[1] Babylonian Talmud, Sotah 35°; Number Rabbah (with Rabbi Jochanàn † 279)