Jeroboam built up the walls of Shechem. It was in the hill country of Ephraim. Jeroboam made Shechem his home. From there he went out and built up Peniel.
References for 1 Kings 12:25
Jeroboam thought, "My kingdom still isn't secure. It could very easily go back to the royal family of David.
Suppose the people of Israel go up to Jerusalem to offer sacrifices at the LORD's temple. If they do, they will again decide to follow Rehoboam as their master. Then they'll kill me. They'll return to King Rehoboam. He is king of Judah."
So King Jeroboam asked for advice. Then he made two golden statues that looked like calves. He said to the people, "It's too hard for you to go up to Jerusalem. Israel, here are your gods who brought you up out of Egypt."
He set up one statue in Bethel. He set up the other one in Dan.
What Jeroboam did was sinful. And it caused Israel to sin. The people even went all the way to Dan to worship the statue that was there.
Jeroboam built temples for worshiping gods on high places. He appointed all kinds of people as priests. They didn't even have to be Levites.
He established a feast. It was on the 15th day of the eighth month. He wanted to make it like the Feast of Booths that was held in Judah. Jeroboam built an altar at Bethel. He offered sacrifices on it. He sacrificed to the calves he had made. He also put priests in Bethel. He did it at the high places he had made.
He offered sacrifices on the altar he had built at Bethel. It was on the 15th day of the eighth month. That's the month he had chosen for it. So he established the feast for the people of Israel. And he went up to the altar to sacrifice offerings.