When One is Enough
Everyone who daily prays in the morning is familiar with Rabbi Yishmaels 13 rules for interpreting laws from the Torah which are not explicitly mentioned. One of these is the kal vchomer. The basic premise of this method is that if the Torah revealed a certain feature in regard to a subject which is kal of a less serious nature then that feature should certainly apply to another subject which is chomer of a more serious nature.
Although the kal vchomer is widely mentioned throughout the Talmud, we find in our gemara a limitation to its application. It is dayoi sufficient that we extend the feature of the kal to the chomer but we cannot endow it with greater proportions.
The source for this limitation is the kal vchomer which G-d mentioned in His response to Moshes plea to heal his sister Miraim from the leprosy-like tzaraat with which Heaven had afflicted her as punishment for slandering her brother. Had her father rebuked her, G-d pointed out, she certainly would have deserved the shame of isolation for seven days, and so He decreed that she should be quarantined for seven days (Bamidbar 12:14).
Using the logic of kal vchomer, say our Sages, should have led to the conclusion that if disrespect for a human father deserves seven days of isolation then double that amount of days should be the punishment for disrespect to G-d who appointed Moshe as His prophet. But since we can extend to the chomer only the dimensions of the kal, the conclusion was seven days only.
Why does the gemara suggest that the affront to G-d should be twice that of a human father? Tosefot cites a gemara (Mesechta Nidah 31a) which states that a newborn receives from each of his parents five components of his being and ten others from G-d. Since G-d endows man with twice as much as the father it would follow that the sin against him is of double gravity and deserves double punishment if not for the limitation of dayoi.
The Beheaded Atonement
The carcass of an animal that died not through shechita is a neveila which imparts tuma ritual impurity to one who touches or carries it. An exception to the rule is the carcass of the egla arufa the calf which is beheaded in connection with an unsolved murder.
The Torah prescribed a ritual for the city nearest to the body of a man found murdered and the identity of the assailant is not known. The elders of that city beheaded a calf and declared that they were not negligent in providing the victim with food and escort and thus bore some responsibility for his death (Devarim 21:1-9).
One phrase used by the Torah in this chapter led the Academy of Rabbi Yannai to conclude that the carcass of that beheaded calf is not considered a spiritually contaminating neveila. "You will be forgiven for this bloodshed" promises G-d to those who perform this ritual. This usage of a term for atonement is found elsewhere in the Torah in regard to sacrifices whose purpose is to achieve atonement for a sinner. Just as an animal which is offered as a sacrifice does not have the status of a neveila, so too does the beheaded calf albeit that it has not been ritually slaughtered enjoy the same exemption from being a source of spiritual contamination.