كتاب النكاح
8  
Marriage
Bulugh al-Maram 1097
Narrated Ibn Abbas (RA):
Allah's Messenger (ﷺ) ordered a man to put his hand on his mouth when he came to the fifth pronouncement and said, "It would be the deciding one." [Reported by Abu Dawud and an-Nasa'i. It's narrators are reliable].
وَعَنِ اِبْنِ عَبَّاسٍ رَضِيَ اَللَّهُ عَنْهُمَا; { أَنَّ رَسُولَ اَللَّهِ ‏- صلى الله عليه وسلم ‏-أَمَرَ رَجُلاً أَنْ يَضَعَ يَدَهُ عِنْدَ اَلْخَامِسَةِ عَلَى فِيهِ, وَقَالَ: "إِنَّهَا مُوجِبَةٌ" } رَوَاهُ أَبُو دَاوُدَ, وَالنَّسَائِيُّ, وَرِجَالُهُ ثِقَات ٌ 1‏ .‏
Reference : Bulugh al-Maram 1097
In-book reference : Book 8, Hadith 1097
English translation : Book 8, Hadith 1108
Hadith Text
Reference