The concept of the Sabbath, the setting apart of one day in seven as a day of rest, was derived from the Mosaic code, the Fourth Commandment directs abstention from labor on the seventh day of the week, and although there is nothing in the New Testament relating to Sunday, the Christian world adopted the first day of the week as a day of rest. Constantine, by an edict in 321 A.D., ordered the suspension on Sunday of all business in the courts of law, except the manumission of slaves, and all other- business except agricultural labor.
Robert O. Hancox S.Ed.,
SUNDAY LAWS-ILLEGALITY OF SUNDAY CONTRACTS,
Mich. L. Rev.
Available at: https://repository.law.umich.edu/mlr/vol45/iss5/6