The Hebrew names of the books of the Torah are named for the first word that appears in each book. The Hebrew name of the the book of Leviticus, therefore, is Vayikra (וַיִּקְרָא), which means “And he called.” This calling refers to God calling out to Moses from inside the Tabernacle. The final letter of that word is an aleph (א) and is silent. When a scribe writes a Torah scroll, this aleph is written noticeably smaller than the other letters of that word.
One interpretation explains that the aleph of Vayikra is small since, out of modesty, Moses initially wanted to write vayikar, which means “he happened”, without an aleph. This would have implied that God happened to speak to him accidentally. This is, in fact, the word used in the story of God speaking to Balaam. God, however, instructed Moses to write the word with an aleph, specifying that God spoke to him intentionally. Moses followed God’s command but, out of modesty, he wrote the aleph small.
Another commentary explains that the “big leph” message from God was what Moses received on Mount Sinai. The “small aleph” message was a lesser, more diluted message that the people were capable of understanding. This was what Moses transmitted from the Tabernacle.
Rabbi Abraham Twerski taught that the letter aleph symbolizes learning Torah:
The message of the diminutive aleph is that one can learn only when one is humble,” Rabbi Twerski wrote. “There are some very bright people who do not learn much because they think they already know everything. Vanity is an obstacle to learning.”
It is interesting to note that the aleph in the name of Adam at the beginning of the Book of Chronicles is written noticeably larger than the other letters, as if to make up for its diminutive counterpart in Vayikra. The sages have suggested that this implies that Adam’s conceit at the pinnacle of creation (contrasting to Moses’ humility) led to his downfall. In this regard, Moses, and the Torah he presented to Israel, was the tikkun (fixing) of the sin of Adam.
Rabbi Jonathan Sacks suggested that the letter implied a lesson about intentionality in service of God:
The letter aleph is almost inaudible. Its appearance in a sefer Torah at the beginning of Vayikra (the “small aleph“) is almost invisible. Do not expect – the Torah is intimating – that the presence of God in history will always be as clear and unambiguous as it was during the Exodus from Egypt and the division of the Red Sea. For much of the time it will depend on your own sensitivity. For those who look, it will be visible. For those who listen, it can be heard. But first you have to look and listen. If you choose not to see or hear, then Vayikra will becomeVayikar. The call will be inaudible. History will seem mere chance.