1 Kings 8:66

8:66 On the fifteenth day after the festival started, he dismissed the people. They asked God to empower the king and then went to their homes, happy and content because of all the good the Lord had done for his servant David and his people Israel.

1 Kings 12:33

A Prophet from Judah Visits Bethel

12:33 On the fifteenth day of the eighth month (a date he had arbitrarily chosen) Jeroboam offered sacrifices on the altar he had made in Bethel. He inaugurated a festival for the Israelites and went up to the altar to offer sacrifices.