Sunan At-Tirmidhi

Narrated Anas bin Malik: That 'Abdur Rahman bin 'Awf and Az-Zubair bin Al-'Awwam complained of lice to the Prophet (ﷺ) during a battle that they participated in. So he permitted them to wear silk shirts. He (Anas) said: ""I saw them wearing them."" [Abu 'Eisa said:] This Hadith is Hasan Sahih