1 Kings 12:30 - Wesley's Explanatory Notes

A sin — That is, an occasion of great wickedness, not only of idolatry, which is called sin by way of eminency; 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. To 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, Judges 18:30, or to shew the peoples 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.