Charles Ellicott Commentary Ezekiel 41:2

"And the breadth of the entrance was ten cubits; and the sides of the entrance were five cubits on the one side, and five cubits on the other side: and he measured the length thereof, forty cubits, and the breadth, twenty cubits." — Ezekiel 41:2 (ASV)

Its length, forty cubits. These are exactly the dimensions of the Holy Place in Solomon’s Temple. The Holy of Holies is not included, being measured by itself in Ezekiel 41:4.