וַיִּ֨בֶן יָרָבְעָ֧ם אֶת־שְׁכֶ֛ם בְּהַ֥ר אֶפְרַ֖יִם וַיֵּ֣שֶׁב בָּ֑הּ וַיֵּצֵ֣א מִשָּׁ֔ם וַיִּ֖בֶן אֶת־פְּנוּאֵֽל׃
Jéroboam fortifia Sichem, sur la montagne d’Ephraïm, et y résida; puis il en sortit et fortifia Penouêl.
Rabbeinu Bahya
ויבא שכמה, “he came to Shechem.” a place destined for a variety of unhappy events (Tanchuma Vayeshev 2). In Shechem Dinah had been raped; In Shechem they sold Joseph. In Shechem the kingdom of David was divided and the ten tribes elected Jerobam as their king. (Kings I 12,1). After Jerobam had been elected king he built up that city (Kings I 12,25).