Built Shechem - In the sense of “enlarged and fortified.” See Daniel 4:30. The first intention of Jeroboam seems to have been to make Shechem his capital, and therefore he immediately set about its fortification. So also he seems to have fortified Penuel for the better security of his Trans-Jordanic possessions (marginal reference).
Related Commentaries of 1 Kings 12:25
1 Kings 12:25
25 Then Jeroboam built Shechem in mount Ephraim, and dwelt therein; and went out from thence, and built Penuel.