John Gill Commentary 1 Kings 6:17

"And the house, that is, the temple before [the oracle], was forty cubits [long]." — 1 Kings 6:17 (ASV)

And the house, that [is], the temple before it
The holy place, which was before the of holies:

was forty cubits [long] ;
and which, with the most holy place, being twenty cubits, as in the preceding verse, made the length of the whole house sixty cubits, as in (1 Kings 6:2) .