Romans 4:13 For the promise that he would be the heir of the world was not to Abraham or to his seed through the law, but through the righteousness of faith.
It's an elusive concept to wrap your mind around but it's actually the core concept of Christianity... Even though it is shared very little... The old covenant was based on us earning our own righteousness before God... All failed... The new covenant is Jesus giving us his righteousness as a gift through faith in him and his work on the cross... It free's us to enjoy and unconditional love and an unconditional blessing... It's really good news... So good it's hard for folks to believe and therein is the challenge :)