The innermost room, the Most Holy, was a perfect cube ten cubits in each dimension.

In the Most Holy stood the Ark of the Covenant, gold overlaid with a solid-gold “mercy seat” or “propitiatory cover,” atop which were two golden cherubs. Above the cover and between the cherubs was a miraculous cloud of light, indicating that God was with his people in the temple, not personally, but by spirit. His holy spirit was active there in providing this light.​—Ex. 25:10-22; Lev. 16:2.

At no time did anyone enter the Most Holy except the high priest, who entered that compartment only on this one day of the year.​—Heb. 9:7.