The incident of Miriam’s leprosy occurred when she and Aaron challenged God’s decision to elevate Moses: “But when the cloud had withdrawn from over the tent, behold, Miriam was leprous, as white as snow. As Aaron turned toward Miriam, behold, she was leprous.he incident of Miriam’s leprosy occurred when she and Aaron challenged God’s decision to elevate Moses: “But when the cloud had withdrawn from over the tent, behold, Miriam was leprous, as white as snow. As Aaron turned toward Miriam, behold, she was leprous.