The Book on Vows and Oaths
كتاب النذور والأيمان عن رسول الله صلى الله عليه وسلم
Chapter 1: What Has Been Related From The Messenger Of Allah (saws) About 'There Is No Vowing For Disobedience'
That the Prophet (ﷺ) said: "There is no vowing in disobedience to Allah, and its atonement is the atonement of an oath."
Chapter 7: What Has Been Related About Making Exceptions In Oath
That the Messenger of Allah (ﷺ) said: "Whoever swears about an oath and says: 'If Allah wills (Insha Allah), then there is no breaking of the oath against him."
Chapter 12: What Has Been Related About How The Prophet (saws) Would Swear
From this father (Ibn Umar) who said: "The Messenger of Allah (ﷺ) often would swear with this oath: 'No! By the Changer of the Hearts.'"
Chapter 16: What Has Been Related About One Who Vows To Perform Hajj By Walking
"I said: 'O Messenger of Allah! My sister vowed that she would walk to the House barefoot and without Khimar (covering).' The Prophet (ﷺ) said: 'Verily Allah will not do anything with the misery of your sister. She should ride, and cover, and fast three days.'"
Chapter 18: What Has Been Related About Fulfilling The Vow Of The Deceased
That Sa'd bin 'Ubadah asked the Messenger of Allah (ﷺ) about a vow that was due from his mother, who died before fulfilling it. The Prophet (ﷺ) said: "Fulfill it for her."