Final answer:
Lehi is believed to have left Jerusalem in approximately 600 BCE according to the Book of Mormon.
Step-by-step explanation:
Lehi, a prominent figure in the Book of Mormon, is said to have left Jerusalem in approximately 600 BCE. According to the narrative, Lehi and his family left Jerusalem to escape the impending destruction and carry out their divine mission in a new land. This event is a significant turning point in the Book of Mormon and is considered a foundational event for the establishment of the Nephite civilization.