God set up the Levitical Priesthood to help with the service of the Tabernacle (Temple): such as offerings made by the Israelites to God. God set up Aaron to be the high priest over the children of Israel and for his sons to acts as ministers for the Lord. We know that all of Israel are descendants from the twelve sons of Jacob. Jacob’s third son was Levi, and Aaron was a fourth generation descendant of Levi. All of his male descendants were chosen by God to be priests forever; it was established by God as an eternal covenant. For the Lord thy God hath chosen him out of all thy tribes, to stand to minister in the name of the Lord, him and his sons for ever (Deut. 18:1,5). And they shall keep all the instruments of the tabernacle of the congregation, and the charge of the children of Israel, to do the service of the tabernacle (Numbers 3:8). The Levitical Priesthood traces through the three sons of Levi whose names are Gershon/Gershom,(Gershonites), Kohath (Kohathites) and Merari (Merarites). This covenant was established for all generations until Christ died on the cross and became our high priest.
Today, we as Christians are considered priest and Christ is our high priest. We do not have to confess our sins before a priest because we can go directly to the throne of grace, which is directly to Jesus Christ. Seeing then that we have a great high priest, that is passed into the heavens, Jesus the Son of God, let us hold fast our profession (Hebrews 4:14). 1 Timothy 2:5 says, For there is one God, and one mediator between God and men, the man Christ Jesus. Ye also, as lively stones, are built up a spiritual house, an holy priesthood, to offer up spiritual sacrifices, acceptable to God by Jesus Christ. But ye are a chosen generation, a royal priesthood, an holy nation, a peculiar people; that ye should shew forth the praises of him who hath called you out of darkness into his marvellous light; (1 Peter 2:5,9).
Hebrews 2:17- Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people.
Hebrews 8:1-Now of the things which we have spoken this is the sum: We have such an high priest, who is set on the right hand of the throne of the Majesty in the heavens.
Hebrews 9:11,12- But Christ being come an high priest of good things to come, by a greater and more perfect tabernacle, not made with hands, that is to say, not of this building; Neither by the blood of goats and calves, but by his own blood he entered in once into the holy place, having obtained eternal redemption for us.
Revelations 5:10- And hast made us unto our God kings and priests: and we shall reign on the earth.