Ezekiel 42:5-9

Now the upper chambers were smaller because the galleries took more space away from them than from the lower and middle ones in the building.

For they were in three stories and had no pillars like the pillars of the courtyards; for that reason the upper chambers were set back from the ground upward, more than the lower and middle ones.

As for the outer wall by the side of the chambers, toward the outer courtyard facing the chambers, its length was fifty cubits.

For the length of the chambers which were in the outer courtyard was fifty cubits; and behold, the length of those facing the main room was a hundred cubits.

And below these chambers was the entrance on the east side, as one enters them from the outer courtyard.