13 For the promise to Abraham and his offspring that he would be heir of the world did not come through the law but through the righteousness of faith. 14 For if it is the adherents of the law who are to be the heirs, faith is null and the promise is void. 15 For the law brings wrath, but where there is no law there is no transgression.
We are saved by grace through faith. Even though we have the law, it is pointing us to putting out faith in Christ. We will never completely uphold the law or even completely know the law. Paul later talks about Abraham’s faith being counted to him as righteousness. Abraham didn’t have the law. The law didn’t come until the time of Moses. It is by faith that we trust in God and His grace and His mercy.