مُوَطَّأُ مَالِكٍ
Muwatta Malik 1028
Vows and Oaths
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَقُولُ لاَ وَمُقَلِّبِ الْقُلُوبِ .
Yahya related to me from Malik that he had heard that the Messenger of Allah, (ﷺ), used tosay, "No, by the Overturner of hearts."
Arabic/English book reference: Book 22, Hadith 15