וַיְהִ֛י הַדָּבָ֥ר הַזֶּ֖ה לְחַטָּ֑את וַיֵּלְכ֥וּ הָעָ֛ם לִפְנֵ֥י הָאֶחָ֖ד עַד־דָּֽן׃
And this thing became a sin; for the people went to worship before the one, even unto Dan.
Read kabbalistic (mystical) interpretation of I Kings 12:30: and classical mystical sources.