Deuteronomy 5:12

שמור OBSERVE [THE SABBATH DAY] — But in the former Ten Commandments (i.e. where they were first promulgated, in Exodus XX.), it states, “Remember [the Sabbath day]"! The explanation is: Both of them (זכור and שמור) were spoken in one utterance and as one word, and were heard in one hearing (i.e. were heard simultaneously) (Mekhilta). כאשר צוך [OBSERVE THE SABBATH DAY TO SANCTIFY IT] AS [THE LORD THY GOD] COMMANDED THEE before the giving of the Law, at Marah (Shabbat 87b).

שָׁמ֛֣וֹר אֶת־י֥וֹם֩ הַשַּׁבָּ֖֨ת לְקַדְּשׁ֑֜וֹ כַּאֲשֶׁ֥ר צִוְּךָ֖֣ ׀ יְהֹוָ֥֣ה אֱלֹהֶֽ֗יךָ׃

Keep the sabbath day to sanctify it, as the Lord thy God has commanded thee.