1 Kings 12:32-33

32Jeroboam 1instituted a feast in the eighth month on the fifteenth day of the month, 2like the feast which is in Judah, and he 3went up to the altar; thus he did in Bethel, sacrificing to the calves which he had made. And he stationed in Bethel 4the priests of the high places which he had made.

33Then he 5went up to the altar which he had made in Bethel on the fifteenth day in the eighth month, even in the month which he had 67devised 8in his own heart; and he 9instituted a feast for the sons of Israel and 10went up to the altar 11to burn 12incense.