Sabbath

A sabbath is a day reserved for rest or prayer, usually each week. The word "Sabbath" comes from the Hebrew word "Shabbat" (). This word is built from the Hebrew root "Sh-B-T," meaning rest. 
In the Hebrew Bible, or "Tanakh," the root "Sh-B-T" is used to describe God resting on the seventh day. This is the day after He finished creating the universe. In the Bible, the idea of "Shabbat," or "Sabbath," as a holy day of rest starts there.
Remembering and keeping Sabbath is also one of the Ten Commandments. From that, the Abrahamic religions (Judaism, Christianity and Islam) all have a tradition of a holy day of rest or prayer set aside every week. These days are now very different from each other, including which day of the week they fall on.
Similar ideas.
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