سُنَنُ النَّسَائِيِّ
Sunan an-Nasa’i 1980
The Book of Funerals
The Numbre of Takbirs in the Funeral Prayer
أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ سَعِيدٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَعَى لِلنَّاسِ النَّجَاشِيَّ وَخَرَجَ بِهِمْ فَصَفَّ بِهِمْ وَكَبَّرَ أَرْبَعَ تَكْبِيرَاتٍ .
It was narrated from Abu Hurairah: That the Messenger of Allah announced the death of An-Najashi to the people, and he led thme out and arranged them in rows, and said the Takbir four times.
Sunan an-Nasa'i, 1980Sahih (Darussalam)