al-Zuhri ابن شهاب الزهري‎, محمد بن مسلم · The Book of Oaths and Vows

"By my father and by my mother." He said: "Allah forbids you to swear by your forefathers." 'Umar said: "By Allah, I never swore by them again, whether saying it for myself or reporting it of others."

"I heard the Messenger of Allah say: 'Whoever vows to obey Allah, let him obey Him, and whoever vows to disobey Allah, let him not disobey Him.'"

"The Messenger of Allah said: 'The best of you are my generation, then those who come after them, then those whom after them, then those who come after them.' -I do not know if he said two times after him or three. Then he mentioned some people who betray and cannot be trusted, who bear witness without being asked to do so, who make vows and do not fulfill them, and fatness will prevail among them."

"The Messenger of Allah passed by a man who was leading another man by a rope. The Prophet took it, and cut it, and he said: 'It is a vow.'"

"My sister vowed to walk to the House of Allah, and she told me to ask the Messenger of Allah about that. So I asked the Prophet for her and he said: 'Let her walk, and let her ride.'"

"Tell her to cover her head and ride, and fast for three days."

"A woman traveled by sea and vowed to fast for a month, but she died before she could fast. Her sister came to the Prophet and told him about that, and he told her to fast on her behalf."

"Fulfill it on her behalf."

"I heard Ka'b bin Malik narrating his Hadith about when he stayed behind and did not join the Messenger of Allah on the campaign to Tabuk. He said: 'When I sat down before him I said: "O Messenger of Allah, as part of my repentance I want to give my wealth in charity to Allah and His Messenger." The Messenger of Allah said: "Keep some of your wealth for yourself; that is better for you." I said: "I will keep…

"I heard Ka'b bin Malik narrating his Hadith about when he stayed behind and did not join the Messenger of Allah on the campaign to Tabuk. (he said) I said: 'As part of my repentance I want to give my wealth in charity for Allah and His Messenger.' The Messenger of Allah said: 'Keep some of your wealth for yourself; that is better for you.' I said: 'I will keep for myself my share that is in Khaibar.'"

"I heard my father Ka'b bin Malik narrate: 'I said: O Messenger of Allah, Allah, the Mighty and Sublime, has saved me by my being truthful, and as part of my repentance I want to give my wealth in charity to Allah and His Messenger. He said: Keep some of your wealth for yourself; that is better for you. I said: I will keep my share that is in Khaibar.'"

"We were with the Messenger of Allah in the year of Khaibar, and we did not get any spoils of war except for wealth, goods and clothes. Then a man from Banu Ad-Dubaib, who was called Rifa'ah bin Zaid, gave the Messenger of Allah a black slave who was called Mid'am. The Messenger of Allah set out for Wadi Al-Qura. When we were in Wadi Al-Qura, while Mid'am was unloading the luggage of the Messenger of Allah, an arrow came…

"The Messenger of Allah said: 'Whoever swears an oath and says: If Allah wills, then he has made an exception.'"

"The Messenger of Allah said: 'Whoever swears an oath and says: If Allah wills, then he has made an exception.'"

"Whoever swears an oath and says, 'If Allah wills,' then he has the choice: If he wishes, he may go ahead, and if he wishes he may not."