Sahih al-Bukhari 2922
Sahih al-Bukhari · Book 56: Fighting for the Cause of Allah (Jihaad) · The wearing of silk in war
Narrated Anas:
حَدَّثَنِي مُحَمَّدُ بْنُ بَشَّارٍ ، حَدَّثَنَا غُنْدَرٌ ، حَدَّثَنَا شُعْبَةُ ، سَمِعْتُ قَتَادَةَ ، عَنْ أَنَسٍ ، رَخَّصَ أَوْ رُخِّصَ لِحِكَّةٍ بِهِمَا .
(Wearing of silk) was allowed to them (i.e. `AbdurRahman and Az-Zubair) because of the itching they suffered from.