صحيح ابن خزيمه
Sahih Ibn Khuzaymah
جماع أبواب صلاة التطوع فى السفر على الدوابChapters on Voluntary Prayers on Mounts while Traveling
(569) بَابُ إِبَاحَةِ صَلَاةِ التَّطَوُّعِ فِي السَّفَرِ عَلَى الْحُمُرِThe chapter on the permissibility of voluntary prayer on donkeys during travel
Hadith Q1268
وَيَخْطِرُ بِبَالِي فِي هَذَا الْخَبَرِ دَلَالَةٌ عَلَى أَنَّ الْحِمَارَ لَيْسَ بِنَجَسٍ وَإِنْ كَانَ لَا يُؤْكَلُ لَحْمُهُ إِذِ الصَّلَاةُ عَلَى النَّجِسِ غَيْرُ جَائِزٍ
I am thinking about this hadith that the donkey is not impure, even though its meat is not eaten, because it is not permissible to pray on something impure.
