1 Kings 12:33

But when he ascended the altar, which he had made, on the fifteenth day of the eighth month, at the festival which he had devised out of his own heart and made a festival for the children of Israel—he ascended the altar to offer incense.

and went up to the altar which he made in Bæthel to sacrifice to the heifers which he made, and he placed in Bæthel the priests of the high places which he had made. And he went up to the altar which he had made, on the fifteenth day in the eighth month, at the feast which he devised out of his own heart; and he made a feast to the children of Israel, and went up to the altar to sacrifice.