וְהָיָ֗ה כְּבֹ֤א מֹשֶׁה֙ הָאֹ֔הֱלָה יֵרֵד֙ עַמּ֣וּד הֶֽעָנָ֔ן וְעָמַ֖ד פֶּ֣תַח הָאֹ֑הֶל וְדִבֶּ֖ר עִם־מֹשֶֽׁה׃
And it came to pass, when Moses entered into the Tent, the pillar of cloud descended, and stood at the door of the Tent; and [the LORD] spoke with Moses.
Read kabbalistic (mystical) interpretation of Exodus 33:9: and classical mystical sources.