Bulugh al-Maram, Book 13, Hadith 2 (In-Book)

In a narration which is Marfu' (attributed to the Prophet) reported by Abu Dawud and an-Nasa'i from Abu Hurairah (RA) it has: "Do not swear by your fathers, nor by your mothers, nor by the rivals (set up as equals with Allah); and do not swear by Allah except when you are speaking the truth."

وَفِي رِوَايَةٍ لِأَبِي دَاوُدَ, وَالنَّسَائِيِّ: عَنْ أَبِي هُرَيْرَةَ ‏- رضى الله عنه ‏- { لَا تَحْلِفُوا بِآبَائِكُمْ, وَلَا بِأُمَّهَاتِكُمْ, وَلَا بِالْأَنْدَادِ, وَلَا تَحْلِفُوا إِلَّا بِاَللَّهِ, وَلَا تَحْلِفُوا بِاَللَّهِ إِلَّا وَأَنْتُمْ صَادِقُونَ" } 1‏.‏ ‏1 ‏- صحيح.‏ رواه أبو داود ( 3248 )‏، والنسائي ( 7 / 5 )‏.‏

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also referenced under: Book 13, Hadith 1375 (English)