knowing that a man is not justified by works of the law but by the faith of Jesus Christ, we also have believed in Jesus Christ, that we may be justified by faith and not by works of the law, because by works of the law shall no flesh be justified.

Is the law then against the promises of God? By no means. For if a law had been given, able to give life, righteousness would really have been by the law;

Behold, I Paul tell you, that if you are circumcised Christ will not profit you.

for not knowing God's righteousness, and seeking to set up their righteousness, they have not submitted themselves to God's righteousness.

but if by grace, no longer by works; for otherwise grace is no longer grace; but if by works, it is no longer grace; for otherwise a work is no longer a work.

If therefore there was perfection through the Levitical priesthood,??or the people received the law under it,??hat need was there that another priest should arise after the order of Melchisedec and not to be called after the order of Aaron?

Christ

by which also you are saved, if you adhere to the word we preached to you, unless indeed you believed in vain.

General references

For if I build up again what I have destroyed, I make myself a transgressor.