When taking an oath, the Prophet ﷺ very often used to say, "No, by Him Who turns the hearts."  

كَثِيرًا مِمَّا كَانَ النَّبِيُّ ﷺ يَحْلِفُ (لاَ وَمُقَلِّبِ الْقُلُوبِ)  

The Prophet ﷺ frequently used to swear, "No, by the One Who turns the hearts."  

أَكْثَرُ مَا كَانَ النَّبِيُّ ﷺ يَحْلِفُ لاَ وَمُقَلِّبِ الْقُلُوبِ  

The oath which the Messenger of Allah ﷺ often used was this: No, by Him who overturns the hearts.  

أَكْثَرُ مَا كَانَ رَسُولُ اللَّهِ ﷺ يَحْلِفُ بِهَذِهِ الْيَمِينِ لاَ وَمُقَلِّبِ الْقُلُوبِ  

From this father (Ibn Umar) who said: "The Messenger of Allah ﷺ often would swear with this oath: 'No! By the Changer of the Hearts.'"  

كَثِيرًا مَا كَانَ رَسُولُ اللَّهِ ﷺ يَحْلِفُ بِهَذِهِ الْيَمِينِ 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."  

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ يَقُولُ لاَ وَمُقَلِّبِ الْقُلُوبِ