וַיִּבֶן֩ אֶת־עֶשְׂרִ֨ים אַמָּ֜ה מירכותי [מִֽיַּרְכְּתֵ֤י] הַבַּ֙יִת֙ בְּצַלְע֣וֹת אֲרָזִ֔ים מִן־הַקַּרְקַ֖ע עַד־הַקִּיר֑וֹת וַיִּ֤בֶן לוֹ֙ מִבַּ֣יִת לִדְבִ֔יר לְקֹ֖דֶשׁ הַקֳּדָשִֽׁים׃
Und er baute zwanzig Ellen auf dem hinteren Teil des Hauses mit Zedernbrettern vom Boden bis zu den Balken; Er baute sie sogar für sich selbst, für ein Heiligtum, sogar für den heiligsten Ort.
Rashi on I Kings
The twenty amohs at the end of the Beis Hamikdosh. The twenty [amohs] which were at the end of the Sanctuary and beyond, and the twenty [amohs] which were at the end of the building, they are the house containing the Ark cover (i.e., the Holy of Holies).
Rashi on I Kings
To the ceiling. He made the walls of cedar until the ceiling to cover the walls of stone in order to coat it with gold.