Deuteronomy 5:15

15 Remember that you were a slave in the land of Egypt, and the Lord your God brought you out from there with a mighty hand and an outstretched arm; therefore the Lord your God commanded you to keep the sabbath day.

Deuteronomy 5:15 In-Context

13 Six days you shall labor and do all your work.
14 But the seventh day is a sabbath to the Lord your God; you shall not do any work—you, or your son or your daughter, or your male or female slave, or your ox or your donkey, or any of your livestock, or the resident alien in your towns, so that your male and female slave may rest as well as you.
15 Remember that you were a slave in the land of Egypt, and the Lord your God brought you out from there with a mighty hand and an outstretched arm; therefore the Lord your God commanded you to keep the sabbath day.
16 Honor your father and your mother, as the Lord your God commanded you, so that your days may be long and that it may go well with you in the land that the Lord your God is giving you.
17 You shall not murder.
New Revised Standard Version Bible, copyright 1989, Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved.