וְֽלֹא־יָ֭דַע כִּֽי־רְפָאִ֣ים שָׁ֑ם בְּעִמְקֵ֖י שְׁא֣וֹל קְרֻאֶֽיהָ׃ (פ)
But he knoweth not that the shades are there; that her guests are in the depths of the nether-world.
Read kabbalistic (mystical) interpretation of Proverbs 9:18: and classical mystical sources.