صحيح ابن خزيمه
Sahih Ibn Khuzaymah
جماع أبواب الأفعال المباحة فى الصلاةChapters on Permissible Acts in Prayer
(330) بَابُ الرُّخْصَةِ فِي بَزْقِ الْمُصَلِّي فِي ثَوْبِهِ وَدَلْكِهِ الثَّوْبَ بَعْضَهُ بِبَعْضٍ فِي الصَّلَاةِ،330 Chapter: Permission to Spit into One’s Garment and Rub It Together in Prayer.
Hadith Q880
وَالدَّلِيلِ عَلَى أَنَّ الْبُزَاقَ لَيْسَ بِنَجَسٍ، إِذْ لَوْ كَانَ نَجِسًا لَمْ يَأْمُرِ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ الْمُصَلِّيَ لِلْبَصْقِ فِي ثَوْبِهِ فِي الصَّلَاةِ
And the explanation of the evidence that saliva is not impure. Because if it were impure and unclean, the Prophet (peace be upon him) would not have ordered the one praying to spit it into his garment during prayer.
