II Chronicles 8:5 Midrash

וַיִּ֜בֶן אֶת־בֵּ֤ית חוֹרוֹן֙ הָֽעֶלְי֔וֹן וְאֶת־בֵּ֥ית חוֹר֖וֹן הַתַּחְתּ֑וֹן עָרֵ֣י מָצ֔וֹר חוֹמ֖וֹת דְּלָתַ֥יִם וּבְרִֽיחַ׃

Also he built Beth-horon the upper, and Beth-horon the nether, fortified cities, with walls, gates, and bars;

Read midrashic interpretation of II Chronicles 8:5: and classical rabbinic exegesis.