Why did Peter describe the Law as a yoke or millstone?
Peter described the Law as a yoke or millstone because it imposed heavy demands no one could keep, and it gave no help to obey. Its penalties were severe—Sabbath-breaking or immorality brought death—so it condemned people as lawbreakers and sinners, revealing their need for salvation.
Les explains that Peter admitted the Law was a yoke and like a millstone around people's throat because of its heavy demand, man's inability to keep it, and the fact that it had nothing to help him do it. Les says the Law was severe: picking up sticks on the Sabbath or being caught in immorality brought death, not a mere slap on the wrist. Yet the cross set people free from all of that. The Law still serves to show why salvation is needed: it condemns, proves everyone guilty as lawbreakers and sinners, and makes a person know they are lost before they can be saved.