Answered by Ustadh Shuaib Ally
Question: Assalamu alaikum wa rahmatullahi wa barakatuh,
Someone thinks in his mind “Ya Allah, I intend to give $ 100 in charity every time I fail to get on time when having an appointment.” When this happens, would this sadaqa then become obligatory on that person?
Answer: Assalaamu ‘alaykum wa rahmatullah,
No, this charity would not become obligatory on that person. This is because the person has not verbalized the oath. Thinking it, or having the intention in one’s mind, is not sufficient in giving the oath legal weight.
For this type of oath to be effective:
-The entire oath would have to be verbal
-The oath does not have to include ‘By Allah’ or ‘For Allah’, because acts of worship are already exclusively for Allah.
-The wording of the oath has to clearly indicate obligation. If it an unclear declaration, a person’s intention that it is obligatory would be sufficient in rendering it obligatory. ‘I will do x’ can indicate the intention of a binding oath, or a mere intention to do something, depending on a person’s intention. The former is binding, the latter not.
Taking the foregoing into consideration: in your scenario, a person saying aloud “Every time I am late, I will donate in charity $100” would be sufficient in rendering it an effective binding oath.
Ramifications of the Above Scenario
In the above scenario, the person can either do what he said he would do every time he is late (donate the amount), or pay the penance for not doing so (kaffara). This is either freeing a female slave; or feeding ten poor persons; or clothing ten poor persons. If one is unable to do any of the three, he must fast three days.
Source: Mughni al-Muhtaj