כִּֽי־נָסַ֨ךְ עֲלֵיכֶ֤ם יְהוָה֙ ר֣וּחַ תַּרְדֵּמָ֔ה וַיְעַצֵּ֖ם אֶת־עֵֽינֵיכֶ֑ם אֶת־הַנְּבִיאִ֛ים וְאֶת־רָאשֵׁיכֶ֥ם הַחֹזִ֖ים כִּסָּֽה׃
For the LORD hath poured out upon you the spirit of deep sleep, And hath closed your eyes; The prophets, and your heads, the seers, hath He covered.
Read kabbalistic (mystical) interpretation of Isaiah 29:10: and classical mystical sources.