The Vilna Gaon was known for his brilliance and Torah scholarship. An example of this scholarship came from his explanation of the Canaanite slave.
The Torah tells us that this particular slave takes on all of the Mitzvot that apply to a woman. In addition, he must go through circumcision and Mikva. If he is freed, he is considered a Jew, in every way.
The difficult law to understand is why he goes free if his master got angry at him, and knocked out his tooth or eye. There are other injuries that would also free him, but the emphasis is on שן ועין, tooth and eye.
The Vilna Gaon explained that slavery was a punishment given to Cham, son of Noach. This was related to the incident when Noach got drunk and was left naked in his tent. Cham or Ham, as he was called in English, used his eyes and saw his father’s nakedness. He used his mouth to tell his brothers about the incident.
The brothers, Shem and Yafet, covered their father with a blanket. They did this without looking at their father.
As an atonement for the sin of Cham, who sinned with his mouth and eyes, the slave goes free when his tooth or eye is knocked. This is an outstanding explanation that only someone like the Vilna Gaon could develop.