other than for Rabbi Akiva, the kiddushin involving chayevei lavin is valid? But why. Rava in Temura holds anything that was done in violation of the torah takes no effect. I realize that there are numerous exceptions. What exception applies here. In other words, why in fact is the kiddushin valid?
allen schuldenfrei, baltimore, maryland USA
1) The Sugya in Temurah 5b actually asks a similar question to yours. The Gemara there asks on Rava from the din that if a widow marries a Kohen Gadol the child relates to the Pagum - the faulted parent, which in this case is the father Chalal, who is an invalidated kohen since he married a woman forbidden to him. The Gemara understands from the words of the Mishnah Kidushin 66b that there is indeed Kidushin in such a case so the question is how is the Kidushin valid b'Di'eved according to Rava since they transgressed the Torah. The Gemara answers that in this case there is a special verse that teaches that the Kidushin is valid .This is what the Torah states that the Kohen Gadol must not desecrate ("Lo Yechalel") his descendants by marrying the forbidden widow. This suggests that the marriage makes "Chalalin" but does not make a Mamzer which teaches that b'Di'eved the marriage is valid. According to Rava the marriage is only valid because there is an explicit verse to this effect.
2) The above passage in Temurah is mentioned by the Rashba in Kidushin 67b DH Eima. The question is that we see from Temurah that we only say that Kidushin is valid with the Kohen Gadol and the widow because there is a verse for this but without a verse the Kidushin would not apply so why is a special verse "A man may not take his fathers wife" required to teach that even if he took her the Kidushin is not "chal"? The Rashba answers that once the Torah revelaed to us that the Kidushin of the Kohen Gadol with the widow is valid I would have thought that we can learn from this case to everywhere else that all forbidden marriages are valid b'Di'eved. The verse "A man may not take his fathers wife" therefore teaches that for the fathers wife it is not "chal" even b'Di'eved.
3) We can learn from the Rashba that for the fathers wife the Kidushin is not chal b'Di'eved (because of the specific verse "lo yikach" - lo yehei Kidushin) but generally speaking for prohibitions which are chayve lavin we do indeed learn from "Lo Yechalel" of the Kohen Gadol and the widow that the Kidushin is effective b'Di'eved.