Hebrews 7:11

Then indeed if perfection was through the Levitical priesthood, for unto it the people have been tithed, what need is there still that another priest shall rise after the order of Melchizedek, and not be called after the order of Aaron?

Hebrews 8:7

For if that first covenant had been faultless, a place would not have been sought for the second.

Galatians 2:21

I do not make void the grace of God: for if righteousness was through law, then Christ died gratuitiously.

Hebrews 5:6

as also he says in another place, Thou art a priest forever after the order of Melchizedek.

Hebrews 7:17-19

For it is testified, Thou art a priest forever after the order of Melchizedek.

Colossians 2:10-17

and you are complete in him, who is the head of all government and authority:

Hebrews 5:10

having been ordained of God a high priest after the order of Melchizedek.

Hebrews 6:20

whither Jesus the forerunner has entered in our behalf, having been made a high priest forever after the order of Melchizedek.

Hebrews 7:15

And it is still more abundantly evident, if after the similitude of Melchizedek another priest rises,

Hebrews 7:21

but He with an oath through the one saying to him, The Lord hath sworn, and will not regret it; thou art a priest forever;

Hebrews 8:10-13

Because this is my covenant which I will establish with the house of Israel after these days, says the Lord; having given my laws in their mind, I will also write them on their heart; and I will be to them a God, and they shall be unto me a people.

Hebrews 10:1-4

For the law having the shadow of good things to come, not the real image of the things, annually with the same sacrifices which they offer continually, is by no means able to make perfect those coming to it:

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?

Bible References

Perfection

Hebrews 7:18
For there is a disannulling of the preceding commandment, on account of its weakness and inadequacy
Hebrews 8:7
For if that first covenant had been faultless, a place would not have been sought for the second.
Hebrews 10:1
For the law having the shadow of good things to come, not the real image of the things, annually with the same sacrifices which they offer continually, is by no means able to make perfect those coming to it:
Galatians 2:21
I do not make void the grace of God: for if righteousness was through law, then Christ died gratuitiously.
Colossians 2:10
and you are complete in him, who is the head of all government and authority:

What

Hebrews 7:26
For such a high priest was indeed appropriate unto us, holy, free from sin, undefiled, having been separated from the sinners, and being higher than the heavens;

Another

Hebrews 7:15
And it is still more abundantly evident, if after the similitude of Melchizedek another priest rises,
Hebrews 5:6
as also he says in another place, Thou art a priest forever after the order of Melchizedek.
Hebrews 6:20
whither Jesus the forerunner has entered in our behalf, having been made a high priest forever after the order of Melchizedek.