'Law of Moses' in the Bible

My concern was because of the false brothers [those people masquerading as Christians] who had been secretly smuggled in [to the community of believers]. They had slipped in to spy on the freedom which we have in Christ Jesus, in order to bring us back into bondage [under the Law of Moses].

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.