Bava Metzia

we derive [the law regarding] a found object from [the law regarding] divorce,  and the other  is of the opinion that we do not derive [the law regarding] a found object from [the law regarding] divorce.  And if you wish I will say: As regards a female minor there is no difference of opinion [and all agree] that we derive [the law regarding] a found object from [the law regarding] divorce, but here they differ regarding a male minor: One  says: We derive [the law regarding] a male minor  from [the law regarding] a female minor, and the other  says: We do not derive [the law regarding] a male minor from [the law regarding a female minor]. And if you wish I will say: One deals with one case  and the other deals with another case, and they do not really differ [as regards the law]. MISHNAH. IF A MAN SEES PEOPLE RUNNING AFTER A LOST ARTICLE [E.G.,] AFTER AN INJURED STAG [OR] AFTER UNFLEDGED PIGEONS,  AND SAYS: 'MY FIELD ACQUIRES POSSESSION FOR ME',  IT DOES ACQUIRE POSSESSION FOR HIM.  BUT IF THE STAG RUNS NORMALLY, OR THE PIGEONS FLY [NATURALLY], AND HE SAYS: 'MY FIELD ACQUIRES POSSESSION FOR ME,' THERE IS NOTHING IN WHAT HE SAYS. GEMARA. Rab Judah said in the name of Samuel: This  is, provided he is present by the side of his field. But ought not his field to acquire it for him [in any case], seeing that R. Jose, son of R. Hanina, said:  A man's 'ground' acquires [property] for him [even] without his knowledge? — These words apply only to a [piece of] 'ground' that is guarded,  but when [the piece] of 'ground' is not guarded, [then the law is that] if [the owner] is present by the side of his field he does [acquire the property], [but] if [he is] not [present] he does not [acquire it]. And whence do you derive that when [the piece of] 'ground' is not guarded [the owner] does [acquire the property] if he is present by the side of the field, [but that he] does not [acquire it] if [he is] not [present]? — From what was taught: If one stands in town and says, 'I know that the sheaf which I have in the field has been forgotten by the labourers,  [and it is my wish that the sheaf] shall not be regarded as forgotten',  I might think that it shall not [in any circumstances]  be regarded as forgotten: the scriptural verse therefore tells us: And thou hast forgot a sheaf in the field [etc.]  implying 'only if thou hast forgotten it [while thou wast] in the field [does the law of the forgotten sheaf apply] and not [if thou hast forgotten it when thou hast returned] to town.' Now, this seems self-contradictory. First you say: 'I might think that it shall not be regarded as forgotten' — from which it would appear that [in fact] it is regarded as forgotten; and then the Gemara  concludes: 'Only if thou hast forgotten it [while thou wast] in the field [does the law of the forgotten sheaf apply] but not [if thou hast forgotten it when thou hast returned] to town' — from which it would appear that [in the case discussed] it is not regarded as a forgotten [sheaf]. It must therefore be assumed that what is meant is this: In the field, [i.e.,] if it was forgotten at the outset, [while the owner was still in the field,] it must be regarded as [a] forgotten [sheaf], [but] if it was remembered [by the owner in the field] and was subsequently forgotten [by the labourers] it is not regarded as [a] forgotten [sheaf]. For what reason? Since he was standing near it [in the field, the field] acquires it for him. But [when the owner is again] in town, even if [the sheaf] was at first remembered [by him] and was forgotten later [by the labourers in the field], it must be regarded as [a] forgotten [sheaf].  For what reason? Because he is not there beside it, so that [the field] does not require possession [of the sheaf] for him. But how does it follow?  Perhaps it is a Biblical decree that [only that which is forgotten by the owner while he is] in the field shall be subject to the law of the forgotten sheaf, but that [when the owner is] in town [again] the sheaf is no more subject to that law?  The Scriptural verse says [further]: Thou shalt not go back to fetch it — this is to include the sheaf which has been forgotten [by the owner on his return] to town. But is not this needed to indicate that disregard of the law involves the transgression of a negative command?  — If that were so, the Scriptural verse would only have to say 'Thou shalt not fetch it'. Why does it say: 'Thou shalt not go back'? [Obviously] in order to include the sheaf which has been forgotten [by the owner on his return] to town. But is not this [additional phrase] still required for [the rule] which we have learned: That which is in front of him [who is engaged in reaping] is not [subject to the law of the] forgotten [sheaf]; that which is behind him is [subject to the law of the] forgotten [sheaf], as it is included in the prohibition: 'Thou shalt not go back [to fetch it]'.  This is the general rule: All that can be included in the prohibition 'Thou shalt not go back [to fetch it]' is [subject to the law of the] forgotten [sheaf]; all that cannot be included in the prohibition 'Thou shalt not go back [to fetch it]' is not [subject to the law of the] forgotten [sheaf]?  — R. Ashi said: The Scriptural verse says: It shall be [for the stranger]  etc., so as to include that which has been forgotten [by the owner when he is back] in town. 'Ulla also said:  'This is, provided that he is present by the side of his field'. And Rabbah b. Bar Hanah said likewise: 'This is, provided that he is present by the side of his field'. R. Abba placed before 'Ulla the following objection: It happened once that Rabban Gamaliel and some elders were going in a ship.  Rabban Gamaliel then said: The tithe which I shall measure off [when I come home] is given [by me] to Joshua.