Exodus 36:27 Kabbalah

וּֽלְיַרְכְּתֵ֥י הַמִּשְׁכָּ֖ן יָ֑מָּה עָשָׂ֖ה שִׁשָּׁ֥ה קְרָשִֽׁים׃

And for the hinder part of the tabernacle westward he made six boards.

Read kabbalistic (mystical) interpretation of Exodus 36:27: and classical mystical sources.