A major rule was stated [by the Sages] concerning the Sabbath: Anyone who forgot the essence of the Sabbath, and performed many labors on many Sabbaths, is liable for but one sin offering; one who knew the essence of the Sabbath, and performed many labors on many Sabbaths, is liable for every Sabbath; one who knew that it is the Sabbath, and performed many labors on many Sabbaths, is liable for every primary [category of] labor; one who [knew that it is the Sabbath, and] performed many labors of one [category of] labor, is liable for but one sin offering.