What is the ruling regarding an oath sworn against drinking from 'Al-Furat' (The Euphrates)?
Chapter on Explicit Divorce and Others
Al-Mughni
Book of Divorce
Primary text
If one swears not to drink from 'Al-Furat' (with the definite article 'Al'), the oath is only broken by drinking from the specifically known river named Al-Furat. If the oath is sworn not to drink from 'water of Furat' (indefinite), the oath is broken by drinking from any sweet water, as the indefinite term refers generally to all that is called 'Furat' (sweet and palatable). This generality is supported by the verses concerning sweet and fresh water, such as Quran 77:27 and Quran 35:12.
Supporting text
If the swearer intended the other possible meaning (the specific river when using the indefinite form, or the general when using the definite form), that intention is accepted because it is a plausible interpretation.