Special Permission to wear Silk
Abu Salama bin Abdir Rahman narrates that Hazrat Abdur Rahman (ra) bin Auf once went to the Holy Prophet (sa) in complaint about the lice infestation, and pleaded, “O Messenger (sa) of Allah, permit me to wear silk clothing.” The traditional cotton clothing for some reason had a lot of lice at the time. Perhaps after it had spread from his hair, it was not going away and so he requested permission to wear silk clothing to protect against this. So the Holy Prophet (sa) granted him permission to wear it. After the demise of the Holy Prophet (sa) and Hazrat Abu Bakr (ra), when Hazrat Umar (ra) was elected Khalifa, Hazrat Abdur Rahman (ra) bin Auf came to Hazrat Umar (ra) along with his son Abu Salama. Abu Salama was wearing an upper garment made of silk, and so Hazrat Umar (ra) asked, “What is this you are wearing?” Hazrat Umar (ra) then placed his hand near the collar area of Abu Salama and tore the shirt. Hazrat Abdur Rahman (ra) bin Auf then asked Hazrat Umar (ra), “Are you not aware that the Holy Prophet (sa) granted me permission?”, to which Hazrat Umar (ra) replied, “The Holy Prophet (sa) only granted you permission to do so because you complained to him about the lice infestation, and this permission was not extended to anyone else.”
(al-Tabaqaat-ul-Kubra li ibn Sa‘d, Vol. 3, p. 96, Abdur Rahman bin Auf, Dar-ul-Kutub al-Ilmiyyah, Beirut, 1990)