knowing that a man is not justified by works of law, but by faith in Jesus Christ, even we have believed on Christ Jesus, that we may 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 can not be. For if a law had been given which could have given life, surely righteousness would have been by law.

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

For being ignorant of God's plan of justification, and seeking to establish their own plan of justification, they have not submitted to God's plan of justification.

And if the election is by grace, it is no longer by works; otherwise grace is no longer grace.

If, then, there had been a perfect expiation by means of the Levitical priesthood, (for with reference to it, the people received the law,) what further need was there that another priest should be raised up after the order of Melchisedec, and not be called after the order of Aaron?

Christ

by which also you are saved, if you hold fast the word which I preached to you, unless you believed in vain.

General references

For if I build again those things which I have destroyed, I make myself a transgressor.