1 Kings 12:28-33

After seeking advice, the king made two golden calves. He said to the people, “It is too much for you to go up to Jerusalem. Here are your gods, Israel, who brought you up out of Egypt.” One he set up in Bethel, and the other in Dan. And this thing became a sin; the people came to worship the one at Bethel and went as far as Dan to worship the other. Jeroboam built shrines on high places and appointed priests from all sorts of people, even though they were not Levites. He instituted a festival on the fifteenth day of the eighth month, like the festival held in Judah, and offered sacrifices on the altar. This he did in Bethel, sacrificing to the calves he had made. And at Bethel he also installed priests at the high places he had made. On the fifteenth day of the eighth month, a month of his own choosing, he offered sacrifices on the altar he had built at Bethel. So he instituted the festival for the Israelites and went up to the altar to make offerings.