פירוש על גיטין 5:1

Neither the main part nor the added part of her dower is collected from anything but the poorest quality land. They are not collected from the betterments made to the property after his death, regardless of whether the betterments were made by the inheritors or by the buyers who she comes to repossess. They are only collected from the possessions [of the late husband], not from potential assets. Rem"a: If a father willed a gift to be given to his son after two or three years, or willed that he not be given his portion of the inheritance for two or three years, the property is considered "potential," not "possessed," and the son's wife may not collect her dower from it (Mahar"i Weil no. 40). Some say that if Jacob dies while his son Reuben is alive, and he left a widow who is supported by his estate, Reuben's widow does not collect her dower from those assets, since they are subordinated to his father's widow upon Reuben's death (Mordechai). This is only if the inheritors have no right to clear the widow's alimony [with a lump sum payment], but if they can pay off the widow, Reuben's widow may collect from there (ibid.). Work wages that never reached his hands are called "potential" (Mordechai on Bava Batra). If an object of his was stolen, then he died, and the stolen object was then recovered, it is considered "possessed" (Responsa Maharam). A loan due to the husband is considered "possessed," and she may collect from it, even if the debtor is a Samaritan. Rem"a: All of this only applies to the main and added parts of her dower. But her dowry and other tzon barzel assets have the status of any debt (Magid Mishneh on ch. 16 and Beit Yosef in the name of Nimukei Yosef, Ran, and Rabbenu Yeruham). Some say that nevertheless they are only collected from poor-quality land (Ran on Gittin).