נְב֥וּב לֻחֹ֖ת תַּעֲשֶׂ֣ה אֹת֑וֹ כַּאֲשֶׁ֨ר הֶרְאָ֥ה אֹתְךָ֛ בָּהָ֖ר כֵּ֥ן יַעֲשֽׂוּ׃ (ס)
Hollow with planks shalt thou make it; as it hath been shown thee in the mount, so shall they make it.
Read midrashic interpretation of Exodus 27:8: and classical rabbinic exegesis.