What is the origin of the idiom "the arm of the law" and when to use it?

The idiom "the arm of the law" likely emerged from the idea that the law reaches out like an arm to maintain order and administer justice. The phrase is often used to describe the actions and interventions of law enforcement agencies, such as police officers, in maintaining order, upholding laws, and apprehending criminals. It can be used in news reports, legal discussions, and conversations about crime and punishment.