Numbers 17:10
And the LORD said unto Moses, Bring Aaron’s rod again before the testimony, to be kept for a token against the rebels; and thou shalt quite take away their murmurings from me, that they die not. And the LORD said unto Moses, Bring Aaron’s rod again before the testimony, to be kept for a token against the rebels; and thou shalt quite take away their murmurings from me, that they die not.
The rod is Aaron's rod for the house of Levi, which budded and brought forth buds and blossoms and almonds. It was to be brought again before the testimony, brought back into the tabernacle to be kept there as a lasting witness to succeeding generations. It is kept as a token and lasting sign against the rebels and against rebellion.
It is proof that God chose Aaron's house and family for the priesthood, and this miracle settled the question and the people's doubts about the priesthood. It was meant to quite take away and stop Israel's murmurings and complaints against God's appointment, expressed against Moses and Aaron and against God. By ending continued rebellion, it was meant to keep the people from dying.
The budded rod brought before the testimony to be kept remains kept in the ark in the Most Holy Place of the temple in heaven, together with the golden pot of manna and the tables of stone folded together like a book, beneath the cherubim and exceeding bright glory where God dwells, with Jesus standing by the ark.