CHAPTER: Ambiguity In Oaths.
Narrated Abu Hurairah: The Messenger of Allah صلی اللہ علیہ وسلم as saying: Your oath should be about something regarding which your companion will believe you. Musaddad said: Abdullah bin Abi Salih narrated to me. Abu Dawud said: Both of them refer to the same person: 'Abbad bin Abu Salih and Abdullah bin Abi Salih.
Narrated Suwayd ibn Hanzalah: We went out intending (to visit) the Messenger of Allah صلی اللہ علیہ وسلم and Wail ibn Hujr was with us. His enemy caught him. The people desisted from swearing an oath, but I took an oath that he was my brother. So he left him. We then came to the Messenger of Allah صلی اللہ علیہ وسلم, and I informed him that the people desisted from taking the oath, but I swore that he was my brother. He said: You spoke the truth: A Muslim is a brother of a Muslim.