משנה אויף שמות 31:13

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.