What is the force of “round about”? Rav Mesharshiya said: From here [we learn] that the boundaries [metzarim] are included by the Torah [in the sale of a field].
On the daf / in context: The phrase “in all its border round about” teaches that the purchaser also acquires the boundary strips and trees on the boundary.
Type of Learning
Custom (Bavli — inclusion of field boundaries)
What Is Learned
When one buys a field, “all its border round about” includes the boundary land and the trees growing on the boundary.