بُلُوغُ الْمَرَامِ
Bulugh al-Maram 104
The Book of Purification
The Manners of Answering the Call of Nature
وَلِلْحَاكِمِ: { أَكْثَرُ عَذَابِ اَلْقَبْرِ مِنْ اَلْبَوْلِ } وَهُوَ صَحِيحُ اَلْإِسْنَاد ِ [1] .
and Al-Hakim reported that: “Urination is the main cause of punishment in the grave”. [Its chain of narrators is authentic].
Bulugh al-Maram, 104