Commentary for Ezekiel 41:14

And the width of the front of the House and the fortress to the east was one hundred cubits The fortress and the cell that was behind it that is הַבְּנִיָה, the “structure” - like בִּנְיָן - and the thickness of the walls, all added up to one hundred cubits. For I explained above that the House was thirty cubits wider in front, for the Hall spread out wider than the Heichal and the cells, fifteen cubits to the north and fifteen cubits to the south. Not that the interior of the Hall was wider than the interior of the Heichal, but that the depository for the knives was attached to the Hall on either side.