Hebreus 7:25+ - Bíblia Online

For this Melchizedek, king of Salem, priest of the Most High God, met Abraham returning from the slaughter of the kings and blessed him. 
And to him Abraham gave a tenth part of everything. He is first, by translation of his name, king of righteousness, and then he is also king of Salem, that is, king of peace. 
Without father, without mother, without genealogy, having neither beginning of days nor end of life, but made like the Son of God, he remains a priest continually. 
See how great he was! Even the patriarch Abraham gave him a tenth of the spoils. 
And those descendants of Levi who receive the priestly office have a commandment in the law to take a tenth from the people, that is, from their brethren, though these also are descended from Abraham. 
But this man whose genealogy is not derived from them received a tenth from Abraham and blessed him who had the promises. 
And without dispute the lesser person is blessed by the greater. 
In this case tithes are received by mortal men, but in that case by one of whom it is witnessed that he lives on. 
One might even say that Levi himself, who receives tithes, paid tithes through Abraham, 
for he was still in the loins of his ancestor when Melchizedek met him. 
Now if perfection could have been through the Levitical priesthood (for on the basis of it the people received the Law), what further need was there for another priest to arise according to the order of Melchizedek, and not one designated according to the order of Aaron? 
For when there is a change of the priesthood, there must also be a change of the law. 
For the one of whom these things are spoken belonged to another tribe, from which no one has ever served at the altar. 
For it is evident that our Lord was descended from Judah, and in regard to that tribe Moses said nothing about priests. 
This becomes even more evident if another priest arises in the likeness of Melchizedek, 
who has become a priest not on the basis of a law of carnal requirement, but according to the power of an indestructible life. 
For it is declared of him, »You are a priest forever,after the order of Melchizedek.« 
On the one hand, a former commandment is set aside because of its weakness and uselessness 
(for the law made nothing perfect); and on the other hand, a better hope is introduced, through which we draw near to God. 
And it was not without an oath. 
Those who formerly became priests took their office without an oath, but he became a priest with an oath through the One who said to him, »The Lord has swornand will not change his mind,You are a priest forever.« 
Because of this oath, Jesus has become the guarantee of a better covenant. 
The former priests were many in number, because they were prevented by death from continuing in office; 
but he holds his priesthood forever, because he continues for ever. 
Therefore he is able also to save forever those who draw near to God through him, since he always lives to make intercession for them. 
For it was fitting that we should have such a high priest, holy, blameless, unstained, separated from sinners, exalted above the heavens. 
He does not need, like those high priests, to offer up daily sacrifices, first for his own sins and then for the sins of the people, because he did this once for all when he offered up himself. 
For the Law appoints men as high priests who are weak, but the word of the oath, which came after the Law, appoints a Son who has been made perfect forever. 
Hebreus 8