God sends a plague and Aaron makes atonement
God sent a plague on the Israelites for grumbling against Moses. Aaron made atonement for them, and 14,700 died.
Key passages
Nu 16:41–50

The next day all the community of the Israelites grumbled against Moses and Aaron, saying, “You have killed the people of Yahweh!” Then, when the community had gathered against Moses and Aaron, they turned to the tent of assembly, and behold, the cloud covered it, …