[the_daug]

Gal 3:17 And this I say, that the covenant, that was confirmed before of God in Christ, the law, which was four hundred and thirty years after, cannot disannul, that it should make the promise of none effect.
Gal 3:18 For if the inheritance be of the law, it is no more of promise: but God gave it to Abraham by promise.

That is why I think Paul circumcised Timothy, Paul stated that Christ does not disannull the promise.

[LearsFool]

I believe you misread verse 17: There Paul says the law does not disannul the covenant (God's promise to Abraham).

And what is that promise?

"And the scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand unto Abraham, saying, In thee shall all the nations be blessed." (3:8)

Gentiles would be justified by faith, not law. And Jews likewise, just as Abraham was justified by faith, 430 years before the Law of Moses. According to v. 7, "they that are of faith, the same are sons of Abraham."

The law, which came 430 later, could not void the promise. Those who want to bind the law on people as the only way to receive that promise are trying to annul God's promise. As you quoted:

"For if the inheritance is of the law, it is no more of promise: but God hath granted it to Abraham by promise." (3:18)

Paul encountered - and opposed - this false doctrine nearly everywhere he preached.