The book of Vayikra, the third of the five books of Moses, begins with a detailed catalogue of the individual offerings brought for all types of situations. G-d called out to Moshe and invited him into the Tent of Meeting in order to communicate these laws to him. Our Masoret — tradition — requires that the letter Aleph in the word Vayikra be written by the scribe smaller than the other letters of the Torah scroll. It is called Aleph ze-ira- the small Aleph.
Some commentators explain the significance of this law as a reference to humility. Moshe did not want the honor he would get if the Torah announced that Hashem called out to him directly and invited him into a private meeting in the Tent of Meeting. He was forced, however, to write all the letters of the Torah without exception and so he wrote this Aleph smaller than the other letters.
Others add that the Aleph is written small in this particular place, because it is the beginning of the book that deals with service to Hashem through sacrificial offerings. In Tehillim, King David points out that G- d desires a broken spirit — humility — rather than a sizable offering. “Zibhay Elokim ruah nishbarah” — “The sacrifices of G-d are a broken spirit; A contrite heart G-d will not despise.” [Teh 51:16]. As a hint to this concept Moshe wrote the letter Aleph small at the beginning of the book of Vayikra that deals with the subject of sacrificial requirements.
Rabbi Obadiah Hadayah, zt’l, taught that the small Aleph, stands for the number 1, signifying unity. Moshe Rabenu worked diligently as the leader of our people with the goal of maintaining unity. Every Jew is part of the unit called Yehudi and all must feel responsible for every other person in the nation. The Torah hints again at this ideal in the second verse where it says, “Adam — a person — singular — who might offer a sacrifice to G-d, –from the cattle and the sheep you all — plural — shall bring your offering.” The verse opens in singular and closes in plural. When one improves his or her spirituality by serving G-d one is offering on behalf of all the people.