1 Kings 12:30-32

Young's Literal Translation

³⁰ and this thing becometh a sin, and the people go before the one -- unto Dan.

³¹ And he maketh the house of high places, and maketh priests of the extremities of the people, who were not of the sons of Levi;

³² and Jeroboam maketh a festival in the eighth month, in the fifteenth day of the month, like the festival that [is] in Judah, and he offereth on the altar -- so did he in Beth-El -- to sacrifice to the calves which he made, and he hath appointed in Beth-El the priests of the high places that he made.