1 Kings 12:30 - Joseph Benson’s Commentary on the Old and New Testaments

This thing became a sin An occasion of great wickedness, not only of idolatry, which is called sin by way of eminence; nor only of the worship of the calves, wherein they pretended to worship the true God; but also of the worship of Baal, and of the utter desertion of the true God, and of all sorts of impiety. The people went to worship before the one even unto Dan Which is not here mentioned exclusively, for they went also to Beth-el, (1 Kings 12:32-33;) but for other reasons, either because that of Dan was first made, the people in those parts having been long leavened with idolatry, or to show the people's readiness and zeal for idols; that those who lived in or near Beth-el, had not patience to stay till that calf was finished, but all of them were forward to go as far as Dan, which was in the utmost borders of the land, to worship an idol there; when it was thought too much for them to go to Jerusalem to worship God in the manner he had prescribed. The reader will easily observe here, as we have already intimated, that the sin of Jeroboam and the people did not consist in worshipping strange and false gods, but in setting up images, or representations of the true God, and worshipping him under the similitude of a corporeal form, which he had himself expressly forbidden, (Exodus 20:4,) and had severely punished in the case of Aaron; so that the people did not offend through ignorance, because their sacred records informed them of the terrible punishment which God had inflicted before for the like offence, whereby he made it evident how displeasing it was to him.