Deuteronomy 5:15

Remember that thou wast a servant in the land of Egypt, and that the Lord thy God brought thee out thence, with a strong hand and an outstretched arm; for this cause the Lord thy God hath commanded thee to keep the day of the sabbaths and hallow it.

And thou shalt remember that thou wast a slave in the land of Egypt, and the Lord thy God brought thee out thence with a mighty hand, and a high arm: therefore the Lord appointed thee to keep the sabbath day and to sanctify it.