Exodus 16:29
"See, for that the LORD hath given you the sabbath, therefore he giveth you on the sixth day the bread of two days; abide ye every man in his place, let no man go out of his place on the seventh day."
Cross References (ranked by relevance)
Speak thou also unto the children of Israel, saying, Verily my sabbaths ye shall keep: for it is a sign between me and you throughout your generations; that ye may know that I am the LORD that doth sanctify you.
Moreover also I gave them my sabbaths, to be a sign between me and them, that they might know that I am the LORD that sanctify them.
And they returned, and prepared spices and ointments; and rested the sabbath day according to the commandment.
And madest known unto them thy holy sabbath, and commandedst them precepts, statutes, and laws, by the hand of Moses thy servant: