This week's Parashah opens with a peculiar Pasuk: “VaYikra El Moshe,” "He called to Moshe" (VaYikra 1:1), but not, "Hashem called to Moshe.” Rabbeinu Bachya explains that our Parashah resumes from where Pekudei, the previous Parashah, left off. There we read, “VaYchas HeAnan Et Ohel Mo’eid UChvod Hashem Malei Et HaMishkan. VeLo Yachol Moshe Lavo El Ohel Mo’ed Ki Shachan Alav HeAnan UChvod Hashem Malei Et HaMishkan,” "The cloud covered the Ohel Mo’eid, and the glory of Hashem filled the Mishkan. Moshe could not enter the Ohel Mo’eid, for the cloud rested upon it, and the glory of Hashem filled the Mishkan” (Shemot 40:34-35). When VaYikra opens, "He called," “He” refers to that same "glory of Hashem" discussed in Pekudei; that “glory of Hashem” called to Moshe. The call to Moshe was an indication that the Kavod Hashem had constricted itself to the Kodesh HaKodashim, thereby informing Moshe that he could enter the Ohel Mo’eid.
Rabbeinu Bachya furthers his explanation. He writes that this call from the Kavod Hashem to Moshe came from the small letter Alef in the word “VaYikra.” But what does this mean? Rabbi Zev Hoberman explains that there is a verse in the Torah that contains a small letter Hey. In Sefer BeReishit, the Pasuk says, “BeHibaram,” “When they were created” (BeReishit 2:4). Additionally, Devarim includes, “HaLaHashem” (Devarim: 32:6) which contains a large letter Hey. The Vilna Ga’on explains that these two letters, each of which has a Gematria of five, allude to the five similarities between Hashem and man's soul. Hashem is greater than we can conceive, and any divine qualities that the soul has are insignificant compared to Hashem. In order to demonstrate this contrast, one Hey is large, and the other is small. Rabbi Hoberman says that Hashem’s making room for Moshe in the Ohel Mo’eid, required Him to constrict His Glory to a mere shadow of itself, just as the divine qualities that the soul possesses are a mere shadow of Hashem Himself. This is what Rabbeinu Bachya meant when he wrote that the small Hey called to Moshe. For the same reason, the Alef of "VaYikra" is small, for were Hashem to reveal Himself in all of His Glory, even Moshe would not have been able to enter the Ohel Mo’eid.
Rabbi Akiva Yosef Schlesinger proposes another reason for why “VaYikra” has a small Alef. He writes that the small Alef alludes to a Pasuk in Tehillim which states, “VaTichasereihu Me’at MeElokim,” "You have made him but slightly less than the angels" (8:6). Chazal discuss how there are 50 gates of understanding—and that Moshe merited entering 49 of them. The small letter Alef, whose Gematria is one, alludes to the missing gate that Moshe was unable to enter. Why couldn't Moshe enter that fiftieth gate? Rabbi Schlesinger proposes that that gate of understanding can be attained only in Eretz Yisrael. Because Moshe was not able to go into Eretz Yisrael, he therefore could not reach the 50th level of understanding.