The Aaronic priesthood was done away at the cross and the Melchizedek priesthood is unique to Christ.
The Aaronic priesthood was done away at the crucifixion of Christ, since He has become our permanent high priest. There is no more need for Levitical priests to offer imperfect sacrifices on behalf of the people in the temple. Jesus alone is worthy to hold the Melchizedek priesthood. Any believer today who has been called out of darkness into the light, regardless of age, race, or sex, is a member of the holy and royal priesthood. The believer operates in the highest authority that is offered today, viz., that of being a child of the Lord Omnipotent. Christians have the true priesthood, since they have the true God who gives it to them (Jn. 1:12; Gal. 3:26-29; 1 Tim. 2:5; Heb. 4:14; 5:9-10; 7:11-8:2; 9:24; and 1 Pt. 2:5 and 9).
John 1:11-13
to his own things he came, and his own people did not receive him;
but as many as did receive him to them he gave authority to become sons of God -- to those believing in his name,
who -- not of blood nor of a will of flesh, nor of a will of man but -- of God were begotten. Gal 3:26-29
for ye are all sons of God through the faith in Christ Jesus,
for as many as to Christ were baptized did put on Christ;
there is not here Jew or Greek, there is not here servant nor freeman, there is not here male and female, for all ye are one in Christ Jesus;
and if ye [are] of Christ then of Abraham ye are seed, and according to promise -- heirs. 1Tim 2:4-5
who doth will all men to be saved, and to come to the full knowledge of the truth;
for one [is] God, one also [is] mediator of God and of men, the man Christ Jesus, Hebrews 4:14-16
Having, then, a great chief priest passed through the heavens -- Jesus the Son of God -- may we hold fast the profession,
for we have not a chief priest unable to sympathise with our infirmities, but [one] tempted in all things in like manner -- apart from sin;
we may come near, then, with freedom, to the throne of the grace, that we may receive kindness, and find grace -- for seasonable help. 5:8-10
through being a Son, did learn by the things which he suffered -- the obedience,
and having been made perfect, he did become to all those obeying him a cause of salvation age-during,
having been addressed by God a chief priest, according to the order of Melchisedek, 7:11-17
If indeed, then, perfection were through the Levitical priesthood -- for the people under it had received law -- what further need, according to the order of Melchisedek, for another priest to arise, and not to be called according to the order of Aaron?
for the priesthood being changed, of necessity also, of the law a change doth come,
for he of whom these things are said in another tribe hath had part, of whom no one gave attendance at the altar,
for [it is] evident that out of Judah hath arisen our Lord, in regard to which tribe Moses spake nothing concerning priesthood.
And it is yet more abundantly most evident, if according to the similitude of Melchisedek there doth arise another priest,
who came not according to the law of a fleshly command, but according to the power of an endless life,
for He doth testify -- 'Thou [art] a priest -- to the age, according to the order of Melchisedek;' 7:21-29
and he with an oath through Him who is saying unto him, 'The Lord sware, and will not repent, Thou [art] a priest -- to the age, according to the order of Melchisedek;')
by so much of a better covenant hath Jesus become surety,
and those indeed are many who have become priests, because by death they are hindered from remaining;
and he, because of his remaining -- to the age, hath the priesthood not transient,
whence also he is able to save to the very end, those coming through him unto God -- ever living to make intercession for them.
For such a chief priest did become us -- kind, harmless, undefiled, separate from the sinners, and become higher than the heavens,
who hath no necessity daily, as the chief priests, first for his own sins to offer up sacrifice, then for those of the people; for this he did once, having offered up himself;
for the law doth appoint men chief priests, having infirmity, but the word of the oath that [is] after the law [appointeth] the Son -- to the age having been perfected.
9:24
for not into holy places made with hands did the Christ enter -- figures of the true -- but into the heaven itself, now to be manifested in the presence of God for us; 1Pet 2:1-9
Having put aside, then, all evil, and all guile, and hypocrisies, and envyings, and all evil speakings,
as new-born babes the word's pure milk desire ye, that in it ye may grow,
if so be ye did taste that the Lord [is] gracious,
to whom coming -- a living stone -- by men, indeed, having been disapproved of, but with God choice, precious,
and ye yourselves, as living stones, are built up, a spiritual house, a holy priesthood, to offer up spiritual sacrifices acceptable to God through Jesus Christ.
Wherefore, also, it is contained in the Writing: 'Lo, I lay in Zion a chief corner-stone, choice, precious, and he who is believing on him may not be put to shame;'
to you, then, who are believing [is] the preciousness; and to the unbelieving, a stone that the builders disapproved of, this one did become for the head of a corner,
and a stone of stumbling and a rock of offence -- who are stumbling at the word, being unbelieving, -- to which also they were set;
and ye [are] a choice race, a royal priesthood, a holy nation, a people acquired, that the excellences ye may shew forth of Him who out of darkness did call you to His wondrous light;