125 Kiddushin 3/4-7

(4) Rabbi Meir says, "Any condition that is not like the condition of the men of [the tribe of] Reuven and the men of [the tribe of] Gad is not a [valid] condition; as it says, "Moses said to them, 'If the men of Reuven and the men of Gad will cross with you,'" and it is written, "If they will not cross armed with you" (Numbers 32:29–30). Rabbi Hananiah, son of Gamliel says, "The matter needed to be stated, for if not so, it would be implied that even in the Land of Canaan they would not inherit [a portion of land]."

(5) [With regard to] one who betroths a woman, and [later] says, "I had thought that she was a Kohenet [daughter of a Kohen] and behold she is a Levite;" "A Levite, and behold she is a Kohenet;" "Poor, and behold she is rich;" "Rich, and behold she is poor;" [in all these cases] she is betrothed, because she did not deceive him. [With regard to] one who says to a woman, "You are hereby betrothed to me after I convert;" "After you convert;" "After I am freed;" "After you are freed;" "After your husband dies;" "After your sister dies;" "After your yavam performs chalitzah [the ceremony performed to release a widow of a childless man from the obligation of levirate marriage];" [in all these cases] she is not betrothed. Similarly, [with regard to] one who says to his fellow, "If your wife gives birth to a female, [the child] is hereby betrothed to me," she is not betrothed. If his fellow's wife was visibly pregnant, his words are valid; and if she gives birth to a female, she is betrothed.

(6) [With regard to] one who says to a woman, "You are hereby betrothed to me on condition that I speak on your behalf to the ruler," or "that I work for you as a laborer." If he speaks on her behalf to the ruler, or works for her as a laborer, she is betrothed; if not, she is not betrothed. "On condition that father is willing." If the father is willing, she is betrothed; if not, she is not betrothed. If the father died, she is betrothed. If the son died, we instruct the father to say that he is not willing.

(7) [One who says,] "I had my daughter betrothed, but I do not know to whom I had her betrothed;" and another comes and says, "I betrothed her," he is believed. [If] this one says, "I betrothed her," and this [other] one says, "I betrothed her," they both [must] give a bill of divorce. And if they desire, one gives a bill of divorce and one marries her.