פירוש על שמות 40:35

ולא יכל משה לבא אל אהל מועד AND MOSES WAS NOT ABLE TO COME INTO THE APPOINTED TENT — But another verse says, (Numbers 7:89) “And when Moses came into the appointed tent [to speak with Him then he heard the voice]”! There comes, however, a third verse and reconciles these apparently contradictory verses, for it says here כי שכן עליו הענן “For (or when) the cloud abode thereon (on the appointed tent)”. Hence you may say: so long as the cloud was upon it “he was not able to come into the appointed tent”, but as soon as the cloud disappeared he entered it and spoke with Him (Sifra, Braita d'Rabbi Yishmael 18).

ולא יכול משה לכא אל אהל מועד, and Moses was unable to enter the Tent of Testimony, etc. It seems strange that the "cloud" prevented Moses from entering the Tent seeing that the Torah had told us in Exodus 24,18 that "Moses went inside the cloud, etc." The difference is clear. In Parshat Mishpatim Moses entered the cloud after G'd had summoned him. In this instance no summons from G'd had been forthcoming.

ולא יכול משה לבא אל אהל מועד, at the time it was standing, assembled.