عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يَمِينُكَ عَلَى مَا يُصَدِّقُكَ بِهِ صَاحِبُكَ وَفِي لَفْظٍ بِمَا يُصَدِّقُكَ بِهِ صَاحِبُكَ
It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: Your oath is upon that thing on which your companion is confirming you.