Reference for Bava Batra 254:18

שלח ליה ר' אבא לרב יוסף בר חמא האומר לחבירו עבדי גנבת והוא אומר לא גנבתי מה טיבו אצלך אתה מכרתו לי

afterwards.<span class="x" onmousemove="('comment',' After he made the declaration on the birthright. A person can make a gift of that only which he already has in his possession, but not of that which he may acquire in the future. Consequently the necessity in such a case, for the father's declaration. ');">¹⁷</span> But according to R. Meir Who said, 'a man may give possession of a thing that has not come into existence',<span class="x" onmousemove="('comment',' Lit., 'to the world'. ');">¹⁸</span> what need is there for, he shall acknowledge?<span class="x" onmousemove="('comment',' Surely he could, according to R. Meir, make a gift to the firstborn, of the double portion. in any property that he might acquire in the future. ');">¹⁹</span> — [It is needed for the case] where property came into his possession<span class="x" onmousemove="('comment',' Lit., 'fell to him'. ');">²⁰</span> while he was dying.<span class="x" onmousemove="('comment',' When he is physically unfit to make any gifts. The law of R. Meir which allows a person to give possession of what he might get in the future, applies only to one who is in a condition to make the gift when it reaches him. A dying man, though legally entitled to obtain possession, is not in a condition to make gifts and to give possession. Hence the necessity for a father's declaration on the birthright. ');">²¹</span> Our Rabbis taught: [Where a son] was held to be a firstborn, and his father declared another [son] to be the firstborn, [the father] is believed. [Where, however, a son] was held not to be a first-born, and his father declared him to be a firstborn, [the father] is not believed. The first [clause harmonises with the view of] R. Judah,<span class="x" onmousemove="('comment',' Who places implicit confidence on the testimony of the father. ');">²²</span> and the last [clause harmonises with that of] the Rabbis.<span class="x" onmousemove="('comment',' Who rely upon repute more than on a father's word. ');">²³</span> R. Johanan said: [If] a person declared, 'this is my son', and then retracted and declared, 'He is my slave', he is not believed. [If, however, he said], 'He is my slave', and then he retracted and declared, 'He is my son', he is believed, for he [may] mean,<span class="x" onmousemove="('comment',' When cising the term, 'Slave'. ');">²⁴</span> 'who attends upon me as a slave'. [This law,] however, is reversed [when the statements were made] at a custom house. If, when passing the custom house, he declared, 'This is my son', and then he retracted, and said, 'He is my slave', he is to be believed.<span class="x" onmousemove="('comment',' By his first statement he may have desired to avoid the slave tax. ');">²⁵</span> [If, however,] he declared, 'He is my slave', and then he retracted, and said,'He is my son', he is not believed.<span class="x" onmousemove="('comment',' For, if his latter statement were correct, he would not have declared his son upon whom there is no tax) to be his slave for whom a tax is payable. ');">²⁶</span> An objection was raised: [It was taught:] If a man attended upon another as a son<span class="x" onmousemove="('comment',' Performing for him light services. ');">²⁷</span> and the latter came [before the court] and declared, 'He is my son' and, then, he retracted and stated, 'He is my slave', he is not believed. [If, however], he attended upon him as a slave, and [the latter] came [to the court] and declared, 'he is my slave', and then he retracted, and stated, 'He is my son', he is not believed!<span class="x" onmousemove="('comment',' How, then, could R. Johanan say that a person is believed when he declares one to be his son though he first declared him to be his slave? ');">²⁸</span> — R. Nahman b. Isaac replied: [The case] there<span class="x" onmousemove="('comment',' In the Baraitha cited. ');">²⁹</span> [refers to one] whom he called, 'a slave of a rope of a hundred'.<span class="x" onmousemove="('comment',' Heb. mezar, [H], 'a rope'. A term of contempt for confirmed slaves (Jast.) [Kohut, Aruch, connects it with an Arabic word, denoting 'bag', and renders, 'a slave if a bag of a hundred.'] ');">³⁰</span> What [is meant By] 'a rope of a hundred'? — A rope of a slave [who is worth] a hundred <i>zuz</i>.<span class="x" onmousemove="('comment',' [According to Kohut, ibid, a bag, or price of a slave is a hundred zuz.] ');">³¹</span> R. Abba sent to R. Joseph b. Hama: If one says to another, 'You stole my slave', and the other says, 'I did not steal [him]'. [And when the first inquires, 'In] what capacity [is he] with you?' [the latter replies]. 'You sold him to me,

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