The Prophet ﷺ frequently used to swear, "No, by the One Who turns the hearts."
أَكْثَرُ مَا كَانَ النَّبِيُّ ﷺ يَحْلِفُ لاَ وَمُقَلِّبِ الْقُلُوبِ
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 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
The oath which the Messenger of Allah ﷺ often used was this: No, by Him who overturns the hearts. (Using translation from Abū Dāʾūd 3263)
أَكْثَرُ مَا كَانَ رَسُولُ اللهِ ﷺ يَحْلِفُ بِهَذِهِ الْيَمِينِ يَقُولُ لَا وَمُقَلِّبِ الْقُلُوبِ