Siman 137

One who descends into the field of his fellow and gathered its fruits, and the owner of the field claims that he took them by theft, while this one says that he sold them to him, he is believed with a shevuat hesat as with all movable property. This is so even if there are witnesses that he gathered them and also witnesses who saw the fruits in his hand, such that he has no migo of "the matter never occurred" nor a migo of "I returned them"—for in such a case even regarding movable property he would not be believed, as I wrote in siman 133, and certainly regarding land—nevertheless, he is believed with an oath regarding the fruits he gathered. This is because there is a strong presumption that a person is not so brazen as to go to the field of his fellow and gather the fruits, and presumably he did this with the permission of the owner of the field. And some say that the reason of "not being brazen" applies only when he said beforehand, "I will go and gather the fruits of so-and-so," but without such a statement we do not say this, and his status is like other movable property. Therefore, if there are witnesses that he took them not in the presence of the owner of the field, and they also saw the fruits in his domain, he must return them to the owners, and the owners swear a shevuat hesat that they did not sell them to him; only if it is not known whether he took them not in the presence of the owner of the field is he believed with an oath (Netivot HaMishpat according to the Sma). And some say that his statement does not add or detract at all (ibid.).

For this reason that has been explained, that a person is not so brazen as to go to his fellow's field and gather the fruits, therefore even if the owner of the field is not here and one said, "I will go and gather the fruits of so-and-so's tree which he sold to me," beit din does not need to prevent him, for presumably the truth is so. However, if the owners came before he placed the fruits into his vessels (Taz) and they contradict him, they may stop him, for in the face of the owners' contradiction we cannot rely on this estimation, for if not so, an impudent person would arise and contradict the owners to their faces and gather his fellow's fruits, and you would not leave anyone a life. However, if he already placed the fruits into his vessels, even if his vessels are still placed in the field of the owner of the fruits, he is believed based on this estimation. And some say that all this is when he did so in public, but when he does so in private, we do not allow him when the owners are not here, for we fear that he wishes to steal. And some say that even in private we allow him when he said beforehand, "I will go and gather the fruits of so-and-so." And some say that even a statement is not required (ibid.), only if it is evident that he acts in secret like a thief and guards himself from the sight of people, certainly we do not allow him when the owners are not here (ibid.). And specifically regarding the fruits is he believed based on this estimation, but one who says, "I will go and cut down so-and-so's trees," beit din protests against him, for specifically regarding fruits that are standing to be taken from the tree do we rely on this estimation, but trees that are not standing to be cut down, we do not rely on this estimation. Therefore, if the trees are standing to be cut down, their law is like fruits, and similarly if the fruits are not yet standing to be harvested, their law is like trees (it appears to me). And all that has been explained, that he is believed in the gathering of the fruits, is only when he says that the owners sold him only the fruits, but if he says that he sold him the body of the field or the body of the tree, he is not believed even regarding the fruits, even if he gathered them and placed them in his vessels and even if he brought them into his domain, since he has no deed and did not hold possession for three years, and as will be explained in siman 145.

From the fact that a person is believed when he comes to gather fruit from his fellow's field not in the presence of the owner, and the beit din does not protest against him, one cannot learn from this law for other matters, such as if a person enters his fellow's house to take movable objects or his fellow's shop to take merchandise not in the presence of the owner and the like; for it is obvious that the beit din is commanded not to allow him to take. Only regarding the gathering of fruit, which involves great effort in their gathering, do we state this chazakah that a person is not so brazen as to do so without the owner's permission. But the taking of objects and merchandise, which he takes in a short time, it is impossible to establish this chazakah. And when there are witnesses that he took them without the owner's permission, they compel him to return them even if they did not see the objects and the merchandise in his hand now. And it will be explained in siman 364. And in siman 361 it will be explained whether one who robs his fellow before witnesses must return it to him before witnesses or not (and proof for this law is from the Rif, chapter 7 of Shevuot, the tenth gate, and also to the Gaon there, and to the Ra'avad in Tamim De'im 4:34. Nevertheless, regarding the initial act they agree, and delve into this).