It was narrated that Abu Hurairah said:
"The Messenger of Allah said: 'Do not swear by your fathers, nor by your mothers nor by the idols. Swear only by Allah, and do not swear unless you are sincere.'"
أَخْبَرَنَا أَبُو بَكْرِ بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُعَاذٍ، قَالَ حَدَّثَنَا أَبِي قَالَ، حَدَّثَنَا عَوْفٌ، عَنْ مُحَمَّدِ بْنِ سِيرِينَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لاَ تَحْلِفُوا بِآبَائِكُمْ وَلاَ بِأُمَّهَاتِكُمْ وَلاَ بِالأَنْدَادِ وَلاَ تَحْلِفُوا إِلاَّ بِاللَّهِ وَلاَ تَحْلِفُوا إِلاَّ وَأَنْتُمْ صَادِقُونَ " .
Grade : Sahih (Darussalam)
Reference : Sunan an-Nasa'i 3769
In-book reference : Book 35, Hadith 9
English translation : Vol. 4, Book 35, Hadith 3800
http://sunnah.com/nasai/35/9
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: Avoid suspicion, for suspicion is the gravest lie in talk and
do not be inquisitive about one another and do not spy upon one another and do not feel envy with the other, and nurse no malice, and nurse no aversion and hostility against one another. And be fellow-brothers and servants of Allah.
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