Numbers 17:6
And Moses spake unto the children of Israel, and every one of their princes gave him a rod apiece, for each prince one, according to their fathers’ houses, even twelve rods: and the rod of Aaron was among their rods. And Moses spake unto the children of Israel, and every one of their princes gave him a rod apiece, for each prince one, according to their fathers’ houses, even twelve rods: and the rod of Aaron was among their rods.
Each prince handed Moses one rod marked with the name of his ancestral house, making twelve rods in all. Aaron's rod, marked for Levi, was laid among the rest of the rods. All were placed before the testimony, with the promise that the rod which blossomed would reveal which tribe God had chosen for the priesthood.
That sign came when Aaron's rod budded, blossomed, and yielded almonds, proving that God had appointed Aaron's house to the priesthood and settling the rebellion over that office. The miracle was not left as a passing wonder, for the rod was preserved inside the tabernacle as a witness to coming generations. There it stood as a lasting sign to silence murmuring and to keep the people from disputing God's choice again.