Not farming the land is spoken of as letting the land rest. This can be stated in active form. Alternate translation: "you must observe a Sabbath of solemn rest for the land" or "you must obey the Sabbath law by not farming the land every seventh year" (See: [[rc://en/ta/man/translate/figs-activepassive]] and [[rc://en/ta/man/translate/figs-metaphor]])