Hebrews 7:11

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?

Hebrews 8:7

for if that first were faultless, a place would not have been sought for a second.

Galatians 2:21

I do not make void the grace of God, for if righteousness be through law -- then Christ died in vain.

Hebrews 5:6

as also in another place He saith, 'Thou art a priest -- to the age, according to the order of Melchisedek;'

Hebrews 7:17-19

for He doth testify -- 'Thou art a priest -- to the age, according to the order of Melchisedek;'

Galatians 4:3

so also we, when we were babes, under the elements of the world were in servitude,

Galatians 4:9

and now, having known God -- and rather being known by God -- how turn ye again unto the weak and poor elements to which anew ye desire to be in servitude?

Colossians 2:10-17

and ye are in him made full, who is the head of all principality and authority,

Hebrews 5:10

having been addressed by God a chief priest, according to the order of Melchisedek,

Hebrews 6:20

whither a forerunner for us did enter -- Jesus, after the order of Melchisedek chief priest having become -- to the age.

Hebrews 7:15

And it is yet more abundantly most evident, if according to the similitude of Melchisedek there doth arise another priest,

Hebrews 7:21

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;')

Hebrews 8:10-13

because this is the covenant that I will make with the house of Israel, after those days, saith the Lord, giving My laws into their mind, and upon their hearts I will write them, and I will be to them for a God, and they shall be to Me for a people;

Hebrews 10:1-4

For the law having a shadow of the coming good things -- not the very image of the matters, every year, by the same sacrifices that they offer continually, is never able to make perfect those coming near,

Treasury of Scripture Knowledge

Summary

If therefore perfection were by the Levitical priesthood, (for under it the people received the law,) what further need was there that another priest should rise after the order of Melchisedec, and not be called after the order of Aaron?

General references

Bible References

Perfection

Hebrews 7:18
for a disannulling indeed doth come of the command going before because of its weakness, and unprofitableness,
Hebrews 8:7
for if that first were faultless, a place would not have been sought for a second.
Hebrews 10:1
For the law having a shadow of the coming good things -- not the very image of the matters, every year, by the same sacrifices that they offer continually, is never able to make perfect those coming near,
Galatians 2:21
I do not make void the grace of God, for if righteousness be through law -- then Christ died in vain.
Galatians 4:3
so also we, when we were babes, under the elements of the world were in servitude,
Colossians 2:10
and ye are in him made full, who is the head of all principality and authority,

What

Hebrews 7:26
For such a chief priest did become us -- kind, harmless, undefiled, separate from the sinners, and become higher than the heavens,

Another

Hebrews 7:15
And it is yet more abundantly most evident, if according to the similitude of Melchisedek there doth arise another priest,
Hebrews 5:6
as also in another place He saith, 'Thou art a priest -- to the age, according to the order of Melchisedek;'
Hebrews 6:20
whither a forerunner for us did enter -- Jesus, after the order of Melchisedek chief priest having become -- to the age.

General references

Numbers 20:26
and strip Aaron of his garments, and thou hast clothed with them Eleazar his son, and Aaron is gathered, and doth die there.'