Sunday is often viewed as a day of rest, and blue laws even restricted Sunday activities and business. The origin of the term is murky. It is often said that the original morality laws in Puritan settlements were printed on blue paper, but there is no evidence to confirm that.
Under blue laws, most businesses, including grocery stores, were closed on Sundays. There were generally some exceptions for hospitals, hotels, and restaurants. The Supreme Court ruled that blue laws were constitutional on secular, not religious grounds. The court said the purpose of the laws was to protect workers and families by “securing a day of rest.”