2 Chronicles 3:9 - Albert Barnes' Notes on the Bible

The upper chambers - Compare 1 Chronicles 28:11. Their position is uncertain. Some place them above the holy of holies, which was ten cubits, or fifteen feet lower than the main building (compare 1 Kings 6:2, 1 Kings 6:20); others, accepting the height of the porch 120 cubits 2 Chronicles 3:4, regard the “upper chambers” or “chamber” ὑπερῷον huperōon, Septuagint), as having been a lofty building erected over the entrance to the temple; others suggest that the chambers intended are simply the uppermost of the three sets of chambers which on three sides surrounded the temple (see 1 Kings 6:5-10). This would seem to be the simplest and best explanation, though we cannot see any reason for the rich ornamentation of these apartments, or for David’s special directions concerning them.