The swearing of the Messenger of Allah (saws) by which he would take an oath Sunan Ibn Majah 2092
Arabic hadith text
حَدَّثَنَا أَبُو إِسْحَاقَ الشَّافِعِيُّ، إِبْرَاهِيمُ بْنُ مُحَمَّدِ بْنِ الْعَبَّاسِ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ رَجَاءٍ الْمَكِّيُّ، عَنْ عَبَّادِ بْنِ إِسْحَاقَ، عَنِ ابْنِ شِهَابٍ، عَنْ سَالِمٍ، عَنْ أَبِيهِ، قَالَكَانَتْ أَكْثَرُ أَيْمَانِ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ " لاَ وَمُصَرِّفِ الْقُلُوبِ "
Translation
It was narrated from Salim that his father said
"The swearing most frequently sworn by the Messenger of Allah (ﷺ) was: 'No, by the Controller of the hearts."'