إذا حلف لا يشرب من هذه البئر ينصرف ذلك إلى الاغتراف
An oath not to drink from this well is understood in relation to drawing water from it.
People normally drink water taken from a well with a bucket or vessel. They do not need to place their mouths inside the well. The word “well” identifies the source, while the legally relevant act concerns obtaining and drinking its water.
The discussion even considers an unusual, difficult hypothetical of drinking directly. The lesson is that legal language follows the recognized method and referent, not merely the most physically immediate connection to the noun.