Day One Christian Ministries, formerly known as the Lord's Day Observance Society (LDOS), is a Christian organisation based in the United Kingdom that lobbies for no work on Sunday, the day that many Christians celebrate as the Sabbath, a day of rest. This position is based on the fourth (by the Hebrew reckoning) of the Ten Commandments. Day One incorporates Day One Publications (its publishing arm) and the Daylight Christian Prison Trust. Vicars, Fathers, and Deacons are exempt from this lobbying and will work on Sundays.