John Gill Commentary 1 Chronicles 9:23

"So they and their children had the oversight of the gates of the house of Jehovah, even the house of the tent, by wards." — 1 Chronicles 9:23 (ASV)

So they and their children had the oversight of the gates of
the house of the Lord
They that were appointed in David's time to watch the gates of the temple, their posterity succeeded them in that office; for it was hereditary:

namely, the house of the tabernacle, by wards ;
that which was at Gibeon in David's time, and now one was erected until the temple was built.