Messenger of Allah ﷺ stood beside me at Al-Hudaibiya and the lice were falling from my head in great number. He asked me, "Have your lice troubled you?" I replied in the affirmative. He ordered me to get my head shaved. Kaʿb added, "This Holy Verse:--'And if any of you is ill, or has ailment in his scalp (2.196), etc. was revealed regarding me. "The Prophet ﷺ then ordered me either to fast three days, or to feed six poor persons with one Faraq (three Sas) (of dates), or to slaughter a sheep, etc. (sacrifice) whatever was available.  

قَالَ وَقَفَ عَلَىَّ رَسُولُ اللَّهِ ﷺ بِالْحُدَيْبِيَةِ وَرَأْسِي يَتَهَافَتُ قَمْلاً فَقَالَ يُؤْذِيكَ هَوَامُّكَ قُلْتُ نَعَمْ قَالَ فَاحْلِقْ رَأْسَكَ أَوْ قَالَ احْلِقْ قَالَ فِيَّ نَزَلَتْ هَذِهِ الآيَةُ {فَمَنْ كَانَ مِنْكُمْ مَرِيضًا أَوْ بِهِ أَذًى مِنْ رَأْسِهِ} إِلَى آخِرِهَا فَقَالَ النَّبِيُّ ﷺ صُمْ ثَلاَثَةَ أَيَّامٍ أَوْ تَصَدَّقْ بِفَرَقٍ بَيْنَ سِتَّةٍ أَوِ انْسُكْ بِمَا تَيَسَّرَ