Ezekiel 42:20 in the King James Version
He measured it by the four sides: it had a wall round about, five hundred reeds long, and five hundred broad, to make a separation between the sanctuary and the profane place.
Context
19 He turned about to the west side, and measured five hundred reeds with the measuring reed.
20 He measured it on the four sides. It had a wall around it, the length five hundred cubits, and the width five hundred cubits, to make a separation between that which was holy and that which was common.