שָׁמ֣וֹר תִּשְׁמְר֔וּן אֶת־מִצְוֺ֖ת יְהוָ֣ה אֱלֹהֵיכֶ֑ם וְעֵדֹתָ֥יו וְחֻקָּ֖יו אֲשֶׁ֥ר צִוָּֽךְ׃
היטן זאָלט איר היטן די געבאָט פֿון ה׳ אײַער גאָט, און זײַנע אָנזאָגן און זײַנע געזעצן, װאָס ער האָט דיר באַפֿױלן.
Midrash Tanchuma
Thus you learn that even the dead are aware of the Sabbath day. R. Joshua the son of Hanina declared: The Holy One, blessed be He, said to Israel: “Keep the Sabbath, for it is equal to the entire law.” About the Sabbath, it is written: Keep the Sabbath day (Deut. 5:12), and concerning the law it states: Ye shall diligently keep the commandments (ibid. 6:17). The Sabbath was given through Moses: See that the Lord hath given you the Sabbath (Exod. 16:29), and similarly, the law was given through Moses.