A number of Rishonim, however, are not able to accept this opinion, since – at least in Ashkenaz- the standard text of the ketuvah is zuzei matan dichazi likhi mi’di’orraita, “two hundred zuz that you are entitled to from the Torah.” This would seem to indicate that the ketuvah is from the Torah. Tosafot (Ketuvot 10a, s.v., Amar) concludes that we do in fact rule like Rabban Shimon ben Gamliel, and that the institution of ketuvah is from the Torah. Others reject this conclusion and advise emending the text of the ketuvah to just say “two hundred zuz that you are entitled to.” Rosh (Ketuvot 1:19) suggests a compromise – the ketuvah is a rabbinic institution, but the amount of the two hundred zuz is based on Torah currency, kesef Tzuri. Thus, the text of the ketuvah should be read as “two hundred zuz, which you are entitled to [rabbinically], [computed] according to the [currency of the] Torah.” In the end, this is a debate of the Shulkhan Arukh and the Rema, with the Shulkhan Arukh ruling that we determine the value based on the lower currency, and do not use the text mi’di’orraita, and the Rema stating the we determine it based on the higher currency and use the text mi’di’orraita (Shulkhan Arukh, Even HaEzer, 66:6). This debate continues until today, with Ashkenazic ketuvot using the phrase dichazi likhi mi’di’orraita, and Sefardic ketuvot saying simply dichazi likhi.There is perhaps a better way to resolve the contradiction in the sources whether ketuvah is Biblical or rabbinic. On the one hand, the Gemara states frequently that ketuvah was instituted by the Rabbis in order that it not be too easy for the husband to divorce his wife (Ketuvot 39b), a very pressing concern in a period prior to cherem Rabbeinu Gershon, when a man could divorce his wife against her will. Since the man would have to pay a large sum of money upon divorce, he would think twice before casually and capriciously deciding to divorce his wife. On the other hand, it seems clear that the institution of the ketuvah derives from the Biblical mohar, as is stated by Rabban Shimon ben Gamliel. This was a sum of money – 50 kesef, which equals 200 zuz – that was given by the prospective husband to the bride’s father. The ketuvah, like the mohar, is 200 zuz, and, like the mohar, its 200 zuz value is set specifically for the case when the bride is a virgin. It is hard to escape the conclusion that mohar was the basis for ketuvah, and, in fact, Rashi on the Torah identifies the two (see Rashi, Shemot 22:15 and Ramban there).
It seems that both of these conclusions are correct. Ketuvah is both a Biblical institution based on mohar and a rabbinic institution to prevent too-easy divorce. Let us first consider the reason for the ketuvah. Certainly, the statement that it is to prevent too-easy divorce does not cover the entire, or even the primary, function of the ketuvah. It seems obvious that the primary function of the ketuvah is to ensure that the woman is financially provided for in case of divorce or the husband’s death (remember that wives do not – according to Torah law – inherit their husbands unless special provisions are made for this). In a society where women did not work (and especially when they devoted their married years to building their household and raising their children), they would need to be provided for in such cases. The reason “that it should not be too easy to divorce her” does not seem to address this basic function of the ketuvah.
Beyond this, Tosafot (Ketuvot 39b, s.v. Taama) points out that this reason does not explain why the Rabbis instituted ketuvah for a widowed wife. If the entire reason is to prevent too-easy divorce, it should have been limited to cases of divorce. Tosafot is forced to answer that once the Rabbis instituted it for divorced women, they extended it and applied it to widowed women as well. This answer seems weak, and it points to the fact that ketuvah is more than just a device to prevent of easy divorce.
The answer to this lies in the sugya that discusses the development of the ketuvah (see mishna Ketuvot 80b, Gemara Ketuvot 82b, Tosefta Ketuvot 12:1, and Yerushalmi Ketuvot 8:11). What emerges from these sources is that the ketuvah was originally a sum of money that was given to the bride’s father and put in escrow in case of divorce or the husband’s death. This stage seems to be an early development of the Torah’s mohar – money given to the bride’s father, as in the case of the Torah’s mohar, but to be held for the bride, not to be taken by the father. However, while this provided for the bride if she were left widowed or divorced, it did not prevent the husband from divorcing her too easily. Since the money had already been paid out, he would not hesitate to divorce her when the whim struck him. The Rabbis then changed the institution of the ketuvah, and moved it from a lump sum at the beginning of the marriage to a standing debt to be paid at the end of the marriage. It was this move – from up front to the end, from money to a debt – that was the rabbinic innovation and that was instituted “so that it should not be easy to divorce her.”
Thus, the institution of ketuvah as we have it – a debt to be paid at the end – is rabbinic in origin. At the same time, it is also Biblical, in that it originated in the Torah’s mohar, that it is based on the amount of the mohar, and that its primary function is not to prevent too-easy divorce, but to provide for the wife if she is left without a husband. Thus, we can rule – like Rosh – that ketuvah, as we have it, is rabbinic, and at the same time rule that its value is determined based on the Biblical coinage, because, in the end, the rabbinic ketuvah originated from the Torah’s mohar.
Question: Is the ketuvah d’oraitta or d’rabanan? Answer: It is both.