Keritot 15 - Questions That Rabbi Akiva Asked
Rabban Gamliel and Rabbi Yehoshua went to the meat market of Ema'um, to buy an animal for the wedding feast of Rabban Gamliel's son. Rabbi Akiva met them there and involved them in a discussion. He asked, "If a man inadvertently cohabits with his sister, who is also his father's sister and his mother's sister, what is the law? Does he have to bring only one sacrifice, since it is only one woman, or does he have to bring three, since these are three different prohibitions?" They answers, "We have not heard an explicit decision on this, but we know a similar case. If one cohabits with his five wives who all did not go to a mikva, he needs to bring five sin-offerings. It seems to us that your case can be deduced with a fortiori logic."
What was the question of Rabbi Akiva, if we just learned cases where one brings mutiple offerings? - His case is special, because all prohibitions are in the same group of a "sister." And the logic of the Sages, it too can be refuted - in their cases there are different women, and Rabbi Akiva asked about one!? Rather, there is a phrase in the Torah that teaches this law: " The nakedness of his sister he has uncovered " - these are extra words, which teach that one is liable for each sister-related prohibition.
Rabbi Akiva then asked them about an animal whose limb was almost severed from its body, whether it conveys ritual impurity, and they answered that they heard a similar case related to humans, and suggested that his question can be answered from there.
Art: Sofonisba Anguissola - Two Sisters and a Brother of the Artist