14. Book of Vows and Oaths
١٤۔ كِتَابُ النُّذُورِ وَالْأَيْمَانِ
"The oath by which the Messenger of Allah used to swear was: 'No, by the Controller of the hearts.'" (Using translation from Nasāʾī 3761)
كَانَتْ يَمِينُ رَسُولِ اللَّهِ ﷺ الَّتِي يَحْلِفُ بِهَا «لَا وَمُقَلِّبِ الْقُلُوبِ»