Nehemiah 8:14-15

As they studied the Law, they discovered that the LORD had commanded through Moses that the Israelites should live in shelters during the festival to be held that month. He had said that a proclamation should be made throughout their towns and in Jerusalem, telling the people to go to the hills to get branches from olive, wild olive, myrtle, palm, and other leafy trees. They were to use these branches to make shelters in which they would live during the festival, as prescribed in the Law.