Mishkat al-MasabihChapter 15Hadith 3281
Full Sharh — Mishkat al-Masabih 3281
وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «يَمِينُكَ عَلَى مَا يُصَدِّقُكَ عَلَيْهِ صَاحبك» . رَوَاهُ مُسلم
English Translation
He reported God’s Messenger as saying, "Your oath should be about something regarding which your companion will believe you.” Muslim transmitted it.
Source
Mishkat al-Masabih(مشكاة المصابيح)
Oaths and Vows
Hadith Number
3281