Bava Batra 60 - 66
Rav said, “When one gives a gift he does so with a 'good eye' (a generous attitude).”
This statement on our daf is taught as the basis for the ruling of Rav in a fascinating case which is taught in the gemara.
Two brothers divided the estate which they inherited from their father. Each brother took one of the two adjoining fields, an inner field surrounded by an outer field. While the father was still alive, he had access to the inner field through a path in the outer field. Now, after the division of the inheritance, the heir of the inner field wants to access his field by walking through his brother’s outer field — following in the footsteps of their father, so to speak. However, the brother who owns the outer field claims that his brother, who now owns the inner field, should not have a path of access through his outer field to the inner one unless the “inner” brother pays him for the right to traverse his property (or otherwise he should fly through the air — Rashbam).
Rav Nachman states that this claim of the “outer” brother is valid. Rav, however, says that the brother who owns the inner field is allowed access to his field through the outer field without any payment required.
“In place of your fathers shall be your children" (Tehillim 45:17). The gemara initially suggests that this promise made by King David to the Jewish People is the basis for Rav’s ruling to allow free access to the “inner” brother. The verse in Tehillim indicates that this son inherits this right and privilege from his father, since he wishes to traverse the outer field in order to gain entrance to the inner field in the very same manner as his father used to do.
The conclusion of the gemara, however, is that Rav's position is actually based on an assumption that extends to other forms of litigation as well. This assumption of human nature is that one who sells property does so with a "good eye", meaning with a generous attitude. Just as when one sells another person a well of water in his field we should assume that he also grants him free access to it through his field, so too do we assume that brothers who divide their inheritance also generously grant access to one another.
- Bava Batra 65a