Inside the earthly temple, Aaron's budding rod was kept in front of the Ark of the Covenant in the Holy of Holies. Aaron's budded rod was kept in the Holy of Holies to quell Israel's rebellion and reveal who God's chosen priests were. During the time of Moses, Korah, a descendant of the tribe of Levi, opposed Moses and Aaron and objected to what they were doing. Because of this, Korah and his followers were all killed.

[Numbers 16:1~35] Korah son of Izhar, the son of Kohath, the son of Levi, and certain Reubenites--Dathan and Abiram, sons of Eliab, and On son of Peleth--became insolent and rose up against Moses. With them were 250 Israelite men, well-known community leaders who had been appointed members of the council....(31) As soon as he finished saying all this, the ground under them split apart and the earth opened its mouth and swallowed them, with their households and all Korah's men and all their possessions. They went down alive into the grave, with everything they owned; the earth closed over them, and they perished and were gone from the community. it their cries, all the Israelites around them fled, shouting, "The earth is going to swallow us too!" And fire came out from the LORD and consumed the 250 men who were offering the incense. 

In Old Testament times, the priesthood was given to the Levites, but service in the tabernacle (the temple and most holy place) was only allowed to Aaron and his direct descendants. So Korah, a descendant of Levi, was jealous of them and rebelled against them, but God chose Moses and Aaron. To give proof that He had chosen Moses and Aaron, God had the heads of the twelve tribes bring staves with the names of their tribes written on them and place them in front of the Ark of the Covenant in the Holy of Holies. 

[Numbers 17:1~11] The LORD said to Moses, "Speak to the Israelites and get twelve staffs from them, one from the leader of each of their ancestral tribes. Write the name of each man on his staff. On the staff of Levi write Aaron's name, for there must be one staff for the head of each ancestral tribe. Place them in the Tent of Meeting in front of the Testimony, where I meet with you....(8)The next day Moses entered the Tent of the Testimony and saw that Aaron's staff, which represented the house of Levi, had not only sprouted but had budded, blossomed and produced almonds. Then Moses brought out all the staffs from the LORD's presence to all the Israelites. They looked at them, and each man took his own staff. The LORD said to Moses, "Put back Aaron's staff in front of the Testimony, to be kept as a sign to the rebellious. This will put an end to their grumbling against me, so that they will not die." .Moses did just as the LORD commanded him. 

The fact that God allowed Aaron's rod to sprout is evidence of God's choice of Aaron. God chose to write Aaron's name on the rod, which represented the tribe of Levi, because only Aaron and his direct descendants were given the privilege of working in the Tabernacle (the temple and most holy place). 

[Numbers 18:1~4] The LORD said to Aaron, "You, your sons and your father's family are to bear the responsibility for offenses against the sanctuary, and you and your sons alone are to bear the responsibility for offenses against the priesthood. Bring your fellow Levites from your ancestral tribe to join you and assist you when you and your sons minister before the Tent of the Testimony. They are to be responsible to you and are to perform all the duties of the Tent, but they must not go near the furnishings of the sanctuary or the altar, or both they and you will die. They are to join you and be responsible for the care of the Tent of Meeting—all the work at the Tent--and no one else may come near where you are. 

Therefore, Aaron's rod that sprouted was a sign of the one who held the office of priest and high priest in the sanctuary (temple, holy of holies). But the earthly temple was made a type and shadow of the heavenly temple. The heavenly temple to which the Bible testifies is Joshua, so Aaron's budded rod showed what Joshua would accomplish. 

Through Aaron's budded rod kept in the Holy of Holies, God showed that Aaron and his direct descendants could become priests and high priests. Similarly, the high priest in the heavenly temple will also have a budding staff, which is a sign of his priestly service to God in the new temple.

[ Isaiah 11:1] And there shall come forth a rod out of the stem of Jesse, and a Branch shall grow out of his roots:

[Zechariah 3:8~9 ]" 'Listen, O high priest Joshua and your associates seated before you, who are men symbolic of things to come: I am going to bring my servant, the Branch. See, the stone I have set in front of Joshua! There are seven eyes on that one stone, and I will engrave an inscription on it,' says the LORD Almighty, 'and I will remove the sin of this land in a single day. 

God said that he would make a rod and a shoot come from the stem of this bird, and that he would set up a stone with seven eyes. Who, then, was this prophesied of?

[Revelation 5:6] Then I saw a Lamb, looking as if it had been slain, standing in the center of the throne, encircled by the four living creatures and the elders. He had seven horns and seven eyes, which are the seven spirits of God sent out into all the earth. 

The seven-eyed stone that Zechariah sees is Joshua, who is depicted as a lamb, and the budding rod that appears from the stem of the bird prophesied by Isaiah also foreshadows Jesus. Thus, the words "I will take away the sin of the earth in one day" inscribed on Joshua's body refer to the power of judgment that Joshua possesses. Aaron's budding rod is kept in the Holy of Holies, a sign that Aaron and his direct descendants held the office of high priest in the holy place (temple and holy of holies). However, the earthly temple was created as a type and shadow of the heavenly temple. Therefore, Aaron's budding rod is a prophecy of Joshua, which is evidence that Joshua is the high priest of the heavenly temple. 

[Hebrews 9:11] When Christ came as high priest of the good things that are already here, he went through the greater and more perfect tabernacle that is not man-made, that is to say, not a part of this creation. 

Aaron's rod, kept in the Holy of Holies, is proof that only Joshua and his descendants can be priests in the heavenly temple. The descendants of Joshua to whom the Bible testifies are the early church members who received the Holy Spirit and the two witnesses. Just as Joshua ascended to the position of high priest, the two witnesses, represented by Joshua's descendants, will also become priests and enter the Holy of Holies.

Thus, Aaron's budded rod was a demonstration that only Jesus and the saints who have received His Holy Spirit can be priests in the heavenly temple. But those who do not know this will envy and hate them, just as Korah and his followers did.