(2) باب الْحَلِفِ بِمُصَرِّفِ الْقُلُوبِ
It was narrated from Salim that his father said:
"The oath by which the Messenger of Allah used to swear was: 'No, by the Controller of the hearts.'" (ES)
Reference (ES): Sunan an-Nasa'i 3762 (ES)
In-book reference (ES): Book 35, Hadith 2 (ES)
English translation (ES): Vol. 4, Book 35, Hadith 3793 (ES)