'Observance' in the Bible

And [you have heard how] I surpassed many of my contemporaries among my countrymen in [my advanced study of the laws of] Judaism, as I was extremely loyal to the traditions of my ancestors.

yet we know that a man is not justified [and placed in right standing with God] by works of the Law, but [only] through faith in [God’s beloved Son,] Christ Jesus. And even we [as Jews] have believed in Christ Jesus, so that we may be justified by faith in Christ and not by works of the Law. By observing the Law no one will ever be justified [declared free of the guilt of sin and its penalty].

For if I [or anyone else should] rebuild [through word or by practice] what I once tore down [the belief that observing the Law is essential for salvation], I prove myself to be a transgressor.