According to the Babylonian Talmud, the ketubah was enacted by Simeon ben Shetach so that it might not be a light thing for a man to divorce his wife. The enactment provides for a man’s wife to receive a fixed sum of money, usually accruing from his property, in the event of his divorcing her or of his predeceasing her. Thirteenth-century rabbi, Aharon HaLevi, adds a different reason, writing: “Of the logic behind this one commandment, [we find] that the Torah has commanded us to perform an act before taking a wife, a matter that is intended to show that they are a couple united in wedlock before he lies down with her carnally, and that he not come upon her as one would do to a harlot, where there is no other act that precedes what goes on between them…”

At any rate, the rabbis in ancient times insisted on the marriage couple entering into the ketubah as a protection for the wife. It acted as a replacement of the biblical mohar – the price paid by the groom to the bride, or her parents, for the marriage (i.e., the bride price). The ketubah served as a contract, whereby the amount due to the wife (the bride-price) came to be paid in the event of the cessation of marriage, either by the death of the husband or divorce. The biblical mohar created a major social problem: many young prospective husbands could not raise the mohar at the time when they would normally be expected to marry. So, to enable these young men to marry, the rabbis, in effect, delayed the time that the amount would be payable, when they would be more likely to have the sum. The mechanism adopted was to provide for the mohar to be a part of the ketubah. Both the mohar and the ketubah amounts served the same purpose: the protection for the wife should her support by her husband (either by death or divorce) cease. The only difference between the two systems was the timing of the payment. A modern secular equivalent would be the entitlement to alimony in the event of divorce.