It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the words of oath used by the Messenger of Allah (peace and blessings be upon him), upon which he (peace be upon him) would swear, were these: "La wa Muqallib al-Qulub" (By the One Who turns the hearts).
Hadith Referenceالفتح الربانی / كتاب الأيمان والنذور / 5307
Hadith Gradingمحدثین:صحیح
Hadith Takhrij«أخرجه البخاري: 6628، (انظر مسند أحمد ترقيم الرسالة: 4788 ترقیم بيت الأفكار الدولية: 4788»
Brief Explanation
Benefits: … The "LĀ" at the beginning of "LĀ WA MUQALLIB AL-QULŪB" is either for the negation of the previous statement, or solely for emphasis.