רָב֥וּעַ יִֽהְיֶ֖ה כָּפ֑וּל זֶ֥רֶת אָרְכּ֖וֹ וְזֶ֥רֶת רָחְבּֽוֹ׃
Four-square it shall be and double: a span shall be the length thereof, and a span the breadth thereof.
Read kabbalistic (mystical) interpretation of Exodus 28:16: and classical mystical sources.