2860 — “A vow is but an oath, and its expiation is the expiation for an oath.”
Ahmad recorded it (4/149 and 156) through Ibn Lahiʿah, who said: Kaʿb ibn ʿAlqamah narrated to us; he said: I heard ʿAbd al-Rahman ibn Shumasah say: We came to Abu al-Khayr, and he said: I heard ʿUqbah ibn ʿAmir say: I heard the Messenger of Allah, peace and blessings be upon him, say this. I say: Its narrators are trustworthy, apart from Ibn Lahiʿah, who had poor retention. Yet I found Shaykh al-Islam Ibn Taymiyyah, may Allah have mercy on him, categorically attributing it to the Prophet, peace and blessings be upon him, citing it as evidence that every vow is an oath. He said in al-Fatawa (3/358): “The evidence for this is the saying of the Prophet, peace and blessings be upon him: ‘A vow is an oath.’” If Shaykh al-Islam had found another route for the hadith besides this one, then it is strong; otherwise, it is not. The former possibility is more likely, since the wording he cited differs from this one. And Allah knows best.
The hadith does, however, occur in Sahih Muslim and elsewhere from ʿUqbah in the abbreviated wording: “The expiation for a vow is the expiation for an oath.” Thus, it is a strong corroborating report for the hadith. It has been documented in Irwaʾ al-Ghalil (2586).
I then found the hadith in al-Tabarani’s al-Muʿjam al-Kabir (17/313/866) and Musnad al-Ruyani (folio 54/1), likewise through Ibn Lahiʿah, with wording close to that cited by Ibn Taymiyyah: “A vow is an oath, and its expiation is the expiation for an oath.” However, he said, “Ibn Shumasah from ʿUqbah,” without mentioning Abu al-Khayr between them. This omission may be attributable to Ibn Lahiʿah, for he has been criticized on account of his retention. The more likely version from him is the one that includes Abu al-Khayr, as has preceded in Ahmad’s narration. I found a strong corroborating narrator for him, for al-Tahawi said in Sharh al-Maʿani (2/74–75): Yunus narrated to us; he said: Ibn Wahb narrated to us; he said: ʿAmr ibn al-Harith informed me, from