וְהַבַּ֗יִת אֲשֶׁ֨ר בָּנָ֜ה הַמֶּ֤לֶךְ שְׁלֹמֹה֙ לַֽיהוָ֔ה שִׁשִּֽׁים־אַמָּ֥ה אָרְכּ֖וֹ וְעֶשְׂרִ֤ים רָחְבּ֑וֹ וּשְׁלֹשִׁ֥ים אַמָּ֖ה קוֹמָתֽוֹ׃
And the house which king Solomon built for the LORD, the length thereof was threescore cubits, and the breadth thereof twenty cubits, and the height thereof thirty cubits.
Rashi
and the height was one hundred and twenty But in I Kings (6:2), it is written: “and thirty cubits the height thereof.” How so? The height of the [first] floor from the floor of the house to the ceiling of the first upper story was thirty cubits, and from upper story to upper story up to the highest roof was ninety cubits, as is written: (I Chron. 28:11): “And David gave his son Solomon the pattern of the vestibule and its houses and its treasures and its upper stories.” From there it can be deduced that there were upper stories there.
Bartenura
ראיה לדבר היכל – that its length was forty [cubits] and its width twenty [cubits] and its height thirty [cubits], which are one-half its length and width (see First Kings, Chapter 6, verses 2 and 17 for a description of the First Temple and Tractate Middot, Chapter 4, Mishnayot 6-7 for a description of the Second Temple).