Cross reference
Leviticus 23:41
41 You shall keep it a feast to Yahweh seven days in the year: it is a statute forever throughout your generations; you shall keep it in the seventh month.
Numbers 29:12
12 On the fifteenth day of the seventh month you shall have a holy convocation; you shall do no servile work, and you shall keep a feast to Yahweh seven days:
Nehemiah 8:18
18 Also day by day, from the first day to the last day, he read in the book of the law of God. They kept the feast seven days; and on the eighth day was a solemn assembly, according to the ordinance.