וְאַרְבָּעִ֥ים בָּאַמָּ֖ה הָיָ֣ה הַבָּ֑יִת ה֖וּא הַהֵיכָ֥ל לִפְנָֽי׃
And the house, that is, the temple before [the Sanctuary], was forty cubits long.
Rashi on I Kings
That is the Sanctuary before it. In front of the partition towards the outside.
וְאַרְבָּעִ֥ים בָּאַמָּ֖ה הָיָ֣ה הַבָּ֑יִת ה֖וּא הַהֵיכָ֥ל לִפְנָֽי׃
And the house, that is, the temple before [the Sanctuary], was forty cubits long.