When the prophet Elijah returns at the end of days, he will not come empty-handed. According to the Mekhilta, he will bring three sacred objects that were hidden away centuries ago, presenting them to Israel as proof that the age of redemption has arrived.
The first is the flask of manna — the same jar that Aaron filled in the wilderness and placed before the Ark of the Covenant. The second is the flask of sprinkling waters, the purification mixture described in (Numbers 19:9) that could cleanse a person from contact with the dead. The third is the flask of anointing oil, the holy oil prepared by Moses himself (Exodus 30:31), used to consecrate priests and kings.
Each of these objects represents something Israel lost. The manna proved that God feeds those who trust Him. The sprinkling waters restored ritual purity. The anointing oil conferred divine authority on leaders. Together, they are the toolkit of a restored nation — sustenance, purity, and legitimate sovereignty.
Some sages add a fourth item: the staff of Aaron, complete with its miraculous almonds and blossoms (Numbers 17:25), the rod that budded overnight to prove that Aaron's priesthood was chosen by God. Whether three objects or four, the teaching is the same. Nothing holy is ever truly lost. It is only hidden, waiting for the moment when Israel is ready to receive it again.