At the conclusion of Parashat Pekudei, the Torah states (Shemot 40:35), “VeLo Yachol Moshe Lavo El Ohel Mo’eid Ki Shachan Alav HeAnan,” “And Moshe could not enter the Ohel Mo’eid because the cloud was resting there.” Why can Moshe not manage to enter the Ohel Mo’eid? There are many instances in the Torah in which Moshe enters to speak with Hashem; for example, “UVeVo Moshe El Ohel Mo’eid Ledabeir Ito,” “And when Moshe went into the Ohel Mo’eid to talk with Him” (BeMidbar 7:89). If the Shechinah is in its standard location, why is Moshe, who was never halted by any barrier before and was even capable of ascending Har Sinai, suddenly unable to enter?
Ramban (Shemot 40:34 s.v. VaYechas HeAnan Et Ohel Mo’eid) comments that Moshe can enter only when Hashem permits him to do so. Rav Moshe Feinstein, with an analogous interpretation of the Pasuk, suggests that Moshe is able to enter physically but doesn’t have a grant from Hashem. This is comparable to other instances in which the same concept is applied. For example, the Kohein Gadol can enter the Kodesh HaKodashim only at certain times on Yom Kippur. Indeed, when individuals who aren’t allowed to enter the Mishkan or Beit HaMikdash enter anyway, they are punished. Nadav and Avihu are killed for going into the Mishkan to offer Ketoret when they shouldn’t have, and many Kohanim Gedolim died in the second Beit HaMikdash by entering the Kodesh HaKodashim while being unqualified to serve as Kohein Gadol.
However, this answer does not resolve the issue of why Moshe cannot enter at the end of Parashat Pekudei but can enter at will afterward. Rashbam (Shemot 40:35 s.v. VeLo Yachol Moshe Lavo El Ohel Mo’eid) suggests that Moshe cannot enter the Mishkan immediately after its assembly, when the Shechinah is filling the entire Mishkan. But once the Shechinah rests only between the Keruvim on the Aron, Moshe can enter the rest of the Mishkan. Similarly, Ramban quotes the Chachamim as saying that while the cloud rests on the Mishkan during its first eight days, Moshe cannot enter the Ohel Mo’eid. Only after that time could Moshe enter.
We now understand two opinions that explain why Moshe cannot enter the Ohel Mo’eid. Rashbam believes the restriction is due to physical inability, and Ramban believes it is due to lack of permission. Rav Shimon Schwab ties these two together by explaining that Moshe is the paradigm of the axiom, “habit becomes natural.” Because he is so dedicated to following the word of Hashem, and Hashem hasn’t yet told him to enter, Moshe’s respect for Hashem makes him physically unable to go in.
Similarly, we should always feel the utmost respect towards Hashem. While it might be difficult to reach the point of physical inability to disobey Him, Moshe’s gift is certainly a goal for which to strive. There were Kohanim Gedolim who died in the Beit HaMikdash because they ignored Hashem, and we will restore the Beit HaMikdash by observing His word as Moshe so successfully did.