The construction of the Temple moves from its grand exterior to its intimate interior, revealing a masterful blend of luxurious materials. Although the outer walls were crafted from magnificent hewn stone, the inner design ensured that not a single stone was visible to anyone standing inside [רד״ק, אברבנאל]. To achieve this, the inner walls were lined entirely with cedar boards [מצודת ציון, שטיינזלץ, אברבנאל]. Rather than being attached directly to the stone, these wooden planks were joined together in an interlocking framework [אברבנאל].
This extensive wood paneling served a practical purpose alongside its visual beauty. It provided the necessary foundation for the gold plating that would be added later. Gold cannot be applied directly to bare stone; it must be nailed into a wooden surface [רש״י, מצודת דוד]. The wood coverage extended from the ground all the way up. The primary approach among commentators is that this paneling reached the ceiling, covering the walls to their full height [רד״ק, מצודת דוד, מצודת ציון, שטיינזלץ], though another perspective suggests it reached the walls of the upper attic [רש״י].
For the floor of the Temple, a different material was chosen. The entire ground was covered with cypress boards rather than cedar. Cypress is a harder, heavier, and stronger wood, making it much better suited to withstand constant foot traffic [אברבנאל].
There are differing views on how much of the Temple interior followed this specific design of cedar walls and cypress floors. One approach understands that this description applies to the entire structure, including both the main hall and the Holy of Holies [אברבנאל]. However, another viewpoint limits this specific wood paneling to the main hall alone. According to this perspective, the wood on the walls of the Holy of Holies only reached the upper third of the room, and its floor lacked cypress entirely, featuring gold plated directly over the bare stone ground [מלבי״ם].