Leviticus 23:40-42 New International Version Anglicized (NIVUK)

40. On the first day you are to take branches from luxuriant trees – from palms, willows and other leafy trees – and rejoice before the Lord your God for seven days.

41. Celebrate this as a festival to the Lord for seven days each year. This is to be a lasting ordinance for the generations to come; celebrate it in the seventh month.

42. Live in temporary shelters for seven days: all native-born Israelites are to live in such shelters

Leviticus 23