yet knowing that a man is not justified by works of law, but through faith in Jesus Christ, even we believed on Christ Jesus, that we might be justified by faith in Christ, and not by works of law; because by works of law no flesh shall be justified.

Is the law, then, against the promises of God? It could not be! For, if a law had been given, which was able to make alive, truly righteousness would have been by law;

Behold, I, Paul, say to you, that, if ye be circumcised, Christ will profit you nothing.

for, being ignorant of God's righteousness, and seeking to establish their own, they did not subject themselves to the righteousness of God;

But, if by grace, it is no longer of works; otherwise the grace becomes no longer grace. [But, if of works, it is no longer grace; otherwise, the work is no longer work.]

If, therefore, there was perfection through the Levitical priesthood (for under it the people have received the law), what further need was there, that another Priest should arise according to the rank of Melchizedek, and not be reckoned according to the rank of Aaron?

Christ

through which also ye are saved, if ye hold fast the word which I proclaimed to you, unless ye believed in vain.

General references

For, if I am building up again, what I pulled down, I show myself to be a transgressor.