וְהֵ֨ם וּבְנֵיהֶ֜ם עַל־הַשְּׁעָרִ֧ים לְבֵית־יְהוָ֛ה לְבֵ֥ית־הָאֹ֖הֶל לְמִשְׁמָרֽוֹת׃
So they and their children had the oversight of the gates of the house of the LORD, even the house of the Tent, by wards.
Read midrashic interpretation of I Chronicles 9:23: and classical rabbinic exegesis.