1 Kings 12:33

Overview - 1 Kings 12
1	The Israelites, assembled at Shechem to crown Rehoboam, by Jeroboam make a suit of relaxation unto him.
6	Rehoboam, refusing the old men's counsel, answers them roughly.
16	Ten tribes revolting, kill Adoram, and make Rehoboam flee.
21	Rehoboam, raising an army, is forbidden by Shemaiah.
25	Jeroboam strengthens himself by cities;
26	and by the idolatry of the two calves.

1 Kings 12:33  (King James Version)
So he offered upon the altar which he had made in Bethel the fifteenth day of the eighth month, even in the month which he had devised of his own heart; and ordained a feast unto the children of Israel: and he offered upon the altar, and burnt incense.