وَعَنْ أَبِي هُرَيْرَةَ رضى الله عنه
قَالَ: قَالَ رَسُولُ اَللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ -«يَمِينُكَ عَلَى مَا يُصَدِّقُكَ بِهِ صَاحِبُكَ» وَفِي رِوَايَةٍ: «اَلْيَمِينُ عَلَى نِيَّةِ اَلْمُسْتَحْلِفِ»
The Messenger of Allah (sallallahu alayhi wa sallam) said: “Your oath will be about that matter which your adversary has required you to swear about so that he will believe you.” In another narration: “An oath is to be interpreted according to the intention of the one who requested it (Al-Mustahlif).”.
Bulugh al-Maram 1558, Book 13, Oaths and Vows, Hadith 3. 1 min read