'Observances' in the Bible

All who desire to display their zeal for external observances try to compel you to receive circumcision, but their real object is simply to escape being persecuted for the Cross of Christ.

how much more will the blood of Christ, who through the eternal [Holy] Spirit willingly offered Himself unblemished [that is, without moral or spiritual imperfection as a sacrifice] to God, cleanse your conscience from dead works and lifeless observances to serve the ever living God?