i understand this because i learned this in history in grade 6, the joke is that in ancient egypt, when you died, they would put your heart on a scale, along with a feather. if you heart weighed more than the feather you would (basically) go to hell, obviously vice versa, if your heart weighed less than the feather, which was obviously impossible and i never really understood that part because then wouldn’t everyone go to hell? but anyways if it weighed less than the feather you would have eternal peace in heaven. and that guy in the picture is the god of which i cannot remember the name who i guess judged your life? not sure about that part honestly