The priesthood is confirmed to Aaron by the miracle of the blooming of his rod, which is kept for a monument in the tabernacle.

 1 And the Lord spoke to Moses, saying:  2 Speak to the children of Israel, and take of every one of them a rod by their kindreds, of all the princes of the tribes, twelve rods, and write the name of every man upon his rod.  3 And the name of Aaron shall be for the tribe of Levi, and one rod shall contain all their families:  4 And thou shalt lay them up in the tabernacle of the covenant before the testimony, where I will speak to thee.  5 Whomsoever of these I shall choose, his rod shall blossom: and I will make to cease from me the murmurings of the children of Israel, wherewith they murmur against you.

 6 And Moses spoke to the children of Israel: and all the princes gave him rods one for every tribe: and there were twelve rods besides the rod of Aaron.  7 And when Moses had laid them up before the Lord in the tabernacle of the testimony:  8 He returned on the following day, and found that the rod of Aaron for the house of Levi, was budded: and that the buds swelling it had bloomed blossoms, which spreading the leaves, were formed into almonds.  9 Moses therefore brought out all the rods from before the Lord to all the children of Israel: and they saw, and every one received their rods.  10 And the Lord said to Moses: Carry back the rod of Aaron into the tabernacle of the testimony, that it may be kept there for a token of the rebellious children of Israel, and that their complaints may cease from me lest they die.

[8] "The rod of Aaron for the house of Levi, was budded": This rod of Aaron which thus miraculously brought forth fruit, was a figure of the blessed Virgin conceiving and bringing forth her Son without any prejudice to her virginity.

 11 And Moses did as the Lord had commanded.  12 And the children of Israel said to Moses: Behold we are consumed, we all perish.  13 Whosoever approacheth to the tabernacle of the Lord, he dieth. Are we all to a man to be utterly destroyed?