Bava Batra

so [in the case of] one rented out or given on hire, the appreciation [must be] such as comes naturally and they do not lose thereby [the cost of its] food. In accordance with [whose view is the law  quoted]? — It is [in accordance with that of] Rabbi. For it was taught: a firstborn son is not [entitled] to take a double portion in the appreciation of the estate, which accrued after the death of their father. Rabbi said: I say, A firstborn son does take a double portion in the [natural] appreciation of an estate which accrued after the death of their father,  but not in the appreciation which the orphans produced after the death of their father. If they inherited a bond of indebtedness the firstborn takes a double portion [in the collected debt].  If a bond of indebtedness [for a debt incurred by the father] was produced against them, the firstborn must pay a double portion [of the debt]. If, however, he said, 'I neither give, nor take [the double portion]',  he is allowed [to do so].  What is the reason [for the opinion] of the Rabbis?  Scripture says, Giving him a double portion,  the [All] merciful has, thus, called it a gift;  as a gift [does not become his]  until it comes into his possession,  so the portion of the birthright [does not become his] until it comes into his [father's] possession.  But Rabbi maintains, [since] Scripture says, a double portion,  the portion of the birthright [is to be] compared to the ordinary portion; as the ordinary portion [is his] although it has not yet come into his [father's] possession,  so [is] the portion of the birthright although it has not yet come into his possession. But [as to] the Rabbis also, surely it is written, a double portion? — That [expression indicates that the two portions] to be given to him are to adjoin one another.  But [as to] Rabbi also, surely it is written, Giving him? — That [expression is to indicate] that if he said, 'I neither take, nor give [the double portions],'  he is permitted to do so. R. Papa said: [In the case where] a [young] palm-tree [was bequeathed] and it became stronger, [or a plot of] and and it produced alluvial soil, all  agree that [the firstborn] takes [a double portion].  The dispute only relates to [the case] where hafurah  turned into [well developed] ears of corn, [or where] undeveloped dates turned into [fully developed] dates. [One] Master  is of the opinion that this is regarded as natural appreciation,  and the [other] Master[s]  hold the opinion [that this is a case of complete] transformation. Rabbah b. Hana said in the name of R. Hiyya, 'He who acts  in accordance with the opinion of Rabbi is acting correctly,  [and] he who acts  in accordance with the opinion of the Sages  is acting correctly.'  —