The book of VaYikra begins with a mystery. The verse reads “And He called to Moses, and HaShem spoke to him from the Tent of Meeting, saying, (Leviticus 1:1). The word VaYikra (and He called) ends with the letter “Aleph “that is shrunken in size.
Our sages explain that small “Aleph” with a Midrash that points to Moshe’s trait of humility.