Ezekiel 40:9

Then measured he the porch of the gate, eight cubits; and the posts thereof, two cubits; and the porch of the gate was inward.

Cross-reference

Ezekiel 44:3 describes the prince sitting in this same porch of the gate — connecting the measurement to its future use.

1 Chronicles 28:11 includes the porch in David's temple plans — the same architectural element whose posts are measured here.