וְאַתָּ֞ה דַּבֵּ֨ר אֶל־בְּנֵ֤י יִשְׂרָאֵל֙ לֵאמֹ֔ר אַ֥ךְ אֶת־שַׁבְּתֹתַ֖י תִּשְׁמֹ֑רוּ כִּי֩ א֨וֹת הִ֜וא בֵּינִ֤י וּבֵֽינֵיכֶם֙ לְדֹרֹ֣תֵיכֶ֔ם לָדַ֕עַת כִּ֛י אֲנִ֥י יְהוָ֖ה מְקַדִּשְׁכֶֽם׃
"Et toi, parle aux enfants d’Israël en ces termes: Toutefois, observez mes sabbats car c’est un symbole de moi à vous dans toutes vos générations, pour qu’on sache que c’est Moi, l’Éternel qui vous sanctifie.
Mishnah Shabbat
A great principle they stated in respect to Shabbat: anyone who forgets the fundamental law of Shabbat and performs many labors on many Shabbatot, is liable for only one sin-offering. One who knows the fundamental law of Shabbat and performs many labors on many Shabbatot is liable for a sin-offering for each and every Shabbat. One who knows that it is Shabbat and performs many labors on many Shabbatot, is liable for every primary labor. One who performs many labors belonging to the same category is obligated for only one sin-offering.