The Messenger of Allah ﷺ as saying: Your oath should be about something regarding which your companion will believe you. Musaddad said: 'Abd Allah b. Abi Salih narrated to me. Abu Dawud said: Both of them refer to the same person: 'Abbad b. Abu Salih and 'Abd Allah b. Abi Salih.
قَالَ رَسُولُ اللَّهِ ﷺ يَمِينُكَ عَلَى مَا يُصَدِّقُكَ عَلَيْهَا صَاحِبُكَ قَالَ مُسَدَّدٌ قَالَ أَخْبَرَنِي عَبْدُ اللَّهِ بْنُ أَبِي صَالِحٍ