Sunan Ibn Majah, Book 11, Hadith 2170 (In-Book) ⓘ
It was narrated from Salim that his father said: "The swearing most frequently sworn by the Messenger of Allah was: 'No, by the Controller of the hearts."'
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، قَالَ كَانَتْ أَكْثَرُ أَيْمَانِ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ " لاَ وَمُصَرِّفِ الْقُلُوبِ " .
also referenced under: Hadith 2092 (Reference) & Volume 3, Book 11, Hadith 2092 (DarusSalam)