مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 444
Purification
Washing - Section 2
وَعَنْ عَلِيٍّ رَضِيَ اللَّهُ عَنْهُ: أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «مَنْ تَرَكَ مَوْضِعَ شَعَرَةٍ مِنْ جَنَابَةٍ لَمْ يَغْسِلْهَا فعل بهَا كَذَا وَكَذَا من النَّار» . قَالَ عَليّ فَمن ثمَّ عاديت رَأْسِي ثَلَاثًا فَمن ثمَّ عاديت رَأْسِي ثَلَاثًا فَمِنْ ثَمَّ عَادَيْتُ رَأْسِي ثَلَاثًا. (رَوَاهُ أَبُو دَاوُدَ وَأَحْمَدُ وَالدَّارِمِيُّ إِلَّا أَنَّهُمَا لَمْ يُكَرِّرَا: فَمن ثمَّ عاديت رَأْسِي)
‘Ali reported God's messenger as saying, “If anyone leaves a spot on a hair which has been sexually defiled without washing it, such and such an amount of hell will have to be suffered for it.” ‘Ali said, “On that account I cut my hair; on that account I cut my hair,”* saying it three times. *Lit. "I treated my hair as an enemy." Abu Dawud, Ahmad and Darimi transmitted it, but Ahmad and Darimi did not repeat, “On that account I cut my hair.”
Mishkat al-Masabih, 444ضَعِيف (الألباني)