Albert Barnes Commentary Ezekiel 42:9

"And from under these chambers was the entry on the east side, as one goeth into them from the outer court." — Ezekiel 42:9 (ASV)

The entry from these chambers to the temple-court was by a passage lying to the east fenced off by the wall (Ezekiel 42:7). This passage is described as lying under the chambers, being on the basement, and also having access by steps to the temple-court, which was raised many steps above the outer court.