بُلُوغُ الْمَرَامِ
Bulugh al-Maram 527
The Book of Prayer
وَعَنْ أَنَسٍ - رضى الله عنه - { أَنَّ اَلنَّبِيَّ - صلى الله عليه وسلم -رَخَّصَ لِعَبْدِ اَلرَّحْمَنِ بْنِ عَوْفٍ, وَالزُّبَيْرِ فِي قَمِيصِ اَلْحَرِيرِ, فِي سَفَرٍ, مِنْ حَكَّةٍ كَانَتْ بِهِمَا } مُتَّفَقٌ عَلَيْهِ [1] .
Narrated Anas (RA): The Prophet (ﷺ) gave permission to 'Abdur-Rahman bin 'Auf and az-Zubair to wear silk during the journey because of an itching which they suffered from. [Agreed upon].
Sunnah.com reference: Book 2, Hadith 458