What amount is obligatory when one vows to give charity of 'money' without specifying the quantity?
General Chapter
Al-Mughni
Book of Vows
Primary text
If one vows to give charity of a certain amount of money but mentally intends a specific larger sum, it suffices for him to give whatever he wishes. This is because the term 'money' applies to a lesser amount, and the vow is not binding based on unstated intention. The view supporting this holds that the ruling should attach to what the verbal statement encompasses. Ahmad held similarly regarding vows of fasting or prayer where a larger, unstated quantity was intended; only the explicitly mentioned scope is obligatory.
Supporting text
The logical deduction suggests that the quantity intended should be binding because the speaker intended through his speech what the wording could bear, thus attaching the legal consequence, similar to an oath.