Albert Barnes Commentary Ezekiel 41:6

"And the side-chambers were in three stories, one over another, and thirty in order; and they entered into the wall which belonged to the house for the side-chambers round about, that they might have hold [therein], and not have hold in the wall of the house." — Ezekiel 41:6 (ASV)

Three, one over another, and thirty in order — that is, there were three stories, and each story was divided into thirty chambers.

The wall which was of the house for the side chambers — Not the wall of the temple but another wall (Ezekiel 41:9) parallel to it, which might be said to be “of the house,” that is, belonging to it. The side-chambers of Solomon’s Temple were built against the temple wall. In Ezekiel’s vision, however, the desire to keep the temple even more separate and holy led to a new arrangement. Specifically, another wall was to be built at such a distance from the temple wall, allowing chambers to be constructed against it. These chambers faced the temple wall and opened into a passage or corridor (F), separating them from the temple itself.

That they might have hold, but they had not hold in the wall of the house — that they might have hold, but not have hold on the wall of the house; that is, entirely separating the chambers from the temple wall proper.