´lt was narrated from Ibn 'Abbas that the Prophet (ﷺ) said:` "Whoever makes a vow and does not state it specifically, the expiation (for such a vow) is the expiation for breaking an oath. Whoever makes a vow and is not able to fulfill it, the expiation for that is the expiation for breaking an oath. Whoever makes a vow and is able to fulfill it, let him do so."
Related hadith on this topic
Explanation & Benefits
Shaykh Umar Farooq Saeedi
Benefits and Issues:
This narration is mawquf (stopped at the Companion).
Therefore, it is not a proof in comparison to a marfu‘ (Prophetic) narration.
What is established from authentic marfu‘ narrations,
Its summary has been stated by Imam Shawkani in this way: If a specific vow (nazr) pertains to an act of righteousness but acting upon it is beyond one’s ability,
then the expiation (kaffarah) of an oath (qasam) is due in it.
And if it is within human ability and capacity, then fulfilling it is obligatory,
whether it pertains to the body or to wealth. And if the vow is for an act of disobedience (ma‘siyah),
then not fulfilling it is obligatory.
But in this case, expiation is not necessary. If the vow pertains to a permissible (mubah) matter and it is not beyond human ability,
then that vow will also be binding,
and expiation will also be obligatory in it.
Just as the female Companion who vowed to perform Hajj on foot, the Prophet (sallallahu alayhi wa sallam) forbade her from going on foot,
and ordered her to offer the expiation for riding.
And if the act is beyond human ability, then expiation is obligatory in it.
(Nayl al-Awtar, Chapters on Oaths, Their Expiation, Chapter: One Who Vows a Vow He Cannot Fulfill or Bear: 8/278)
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 3322