1 Kings 12:31-32

31Jeroboam also made shrines on the high places and made priests from the ranks of the people who were not Levites.

32Jeroboam made a festival in the eighth month on the fifteenth day of the month, like the festival in Judah. He offered sacrifices on the altar; he made this offering in Bethel to sacrifice to the calves he had made. He also stationed the priests in Bethel for the high places he had made.