Leviticus 23:39-41

39But on the fifteenth day of the seventh month, when ye have gathered in the produce of the land, ye shall celebrate the feast of Jehovah seven days: on the first day there shall be rest, and on the eighth day there shall be rest.

40And ye shall take on the first day the fruit of beautiful trees, palm branches and the boughs of leafy trees, and willows of the brook; and ye shall rejoice before Jehovah your 1God seven days.

41And ye shall celebrate it as a feast to Jehovah seven days in the year: [it is] an everlasting statute throughout your generations; in the seventh month shall ye celebrate it.