‘And he brought me to the temple and measured the posts, six cubits broad on the one side and six cubits broad on the other side, which was the breadth of the tent. And the breadth of the entrance was ten cubits, and the sides (shoulders) of the entrance were five cubits on the one side and five cubits on the other side. And he measured its length, forty cubits, and its breadth, twenty cubits.'
Now we are entering the ‘nave' of the sanctuary, the holy place. The posts are one cubit larger than for the entry to the vestibule, an indication of the increasing importance of the place being entered. Note the reference to ‘the tent' or tabernacle, a deliberate but subtle linking of the heavenly temple with the tabernacle. But the size of the doorway decreases to ten cubits. The place is holy and entry restricted.
The size of the holy place is forty cubits by twenty cubits. The proportions all match the tabernacle. The holy place is twice the size of the holy of holies, the latter probably being a perfect cube (compare 1 Kings 6:20). The measurements indicate the gradual approach towards ultimate perfection.