There is significant tension between the end of Parashat Pekudei and the beginning of Parashat Vayikra. Parashat Pekudei (and the Book of Shemot) ends with Moshe not able to enter the Ohel Moed:
“Moses could not enter the Tent of Meeting, because the cloud had settled upon it and the Presence of the LORD filled the Tabernacle.” (Shemot 40:35)
However, just a few verses later, at the beginning of Vayikra, we read:
“The LORD called to Moses and spoke to him from the Tent of Meeting, saying:” (Vayikra 1:1)
If Moshe could not enter the Ohel Moed, then how could God speak to him inside it?
The commentators give a few different answers.
Ramban on Shemot 40:34, writes that according to the plain meaning of the text, “Moshe did not enter the Tabernacle, but God called him from the Tent of Meeting and he stood at its door as He spoke to Him.” Moshe could not enter the Ohel Moed, but he could hear God from just outside.
Ibn Ezra on Bamidbar 7:89 gives a different solution. He writes that the laws of the sacrifices in the beginning of the book of Vayikra (starting with Vayikra 1:1) were not presented in chronological order. Later, at the dedication of the mishkan, we read that “Moses and Aaron then went inside the Tent of Meeting.” (Vayikra 9:23). At that point the cloud was no longer preventing entrance to the Ohel Moed. According to Ibn Ezra, God called to Moshe (Vayikra 1:1) happened after the dedication.
But the most common explanation is that at the end of Pekudei Moshe was indeed not allowed to enter the Ohel Moed, and that is why God called him at the beginning of Vayikra – to tell him he was allowed to come inside (Rashbam and Hizzkuni on Vayikra 1:1). While some say that God literally called to Moshe (Daat Mikra on Vayikra 1:1 quoting Midrash Lekach Tov), Rabbeinu Bachye (on Shemot 40:34) says this was a figurative calling: once the cloud was lifted, Moshe knew he had permission to enter the Ohel Moed.
If we accept this last explanation, that Moshe was first prevented from entering the Ohel Moed, but then soon after allowed entry, we may ask – why? Why prevent him from entering at all?
Rav Hirsch on Shemot 40:18 offers an answer. He writes: “Finally, on the eighth day, the first of Nissan, Moses erected the ‘Abode’ […] when Moses had completed the work, then ‘the cloud covered the Glory of God filled the Mishkan […] As soon as Moses had completed the work of erecting the Mishkan, he immediately retired in his relation towards it, to the status of one of the rest of the nation. It was not ‘his’ work, not ‘his’ relationship to the Divine Laws […] it was the nation for whom God had allowed His Glory to enter into the home of Torah on earth, and there to reside. In that supreme moment of God’s relation to Israel, even Moses at first stepped back into the ranks of the people. Only then did he receive a fresh call [the ‘calling’ in Vayikra 1:1] now to learn for the nation from this Tent of Meeting the demands which the presence of God in their midst made…”
To continue his line of thought, I would add that the Book of Shemot concluded as it did because it saw the transition from the Giving of the Torah at Mount Sinai to the establishment of the Mishkan. That was an objective on its own, and in its completion, only God’s presence could be allowed in the Ohel Moed. The next book, Vayikra, had a different perspective. In it, Moshe would receive the divine laws from within the Ohel Moed – no longer at Sinai. And those laws would be, as Rav Hirsch said, about how to maintain holiness and purity, to allow God to continue to reside in the Mishkan. To begin this new approach, Moshe needed to enter the Ohel Moed afresh.