God has specifically chosen the line of priests to come through the tribe of Levi. Aaron (from tribe of Levi… Moses’ brother) was the first high priest. But there were some who felt they should be priest. Korah (from the tribe of Levi) was discontent with his job in the tabernacle. He wanted more. He wanted to be priest. So, he (joined by Dathan and Abiram) confronted Moses and Aaron – disrespectfully and in sin. Moses responded by turning to God, pointing that it is God who choses. Clearly, God does not chose those men because He judges and consumes them out of the face of the earth. Yet, the people of Israel still complain and question Aaron as the rightful and chosen priest from God. God puts an end to this with His rod bud test where the clear victor is Aaron’s rod which not only budded but also sprung up fruit.