Now when all the congregation saw that Aaron was dead, all the house of Israel mourned for Aaron thirty days.
Surrounding context
20:28 Moses stripped Aaron of his garments and put them on Eleazar his son; and Aaron died there on the top of the mountain. Then Moses and Eleazar came down from the mountain.
20:29 Now when all the congregation saw that Aaron was dead, all the house of Israel mourned for Aaron thirty days.