صحيح البخاري

Narrated Abu `Uthman:

While we were with `Utba. `Umar wrote to us: The Prophet (ﷺ) said, "There is none who wears silk in this world except that he will wear nothing of it in the Hereafter." ' Abu `Uthman pointed out with his middle and index fingers.

This hadith has also been narrated by Abu `Uthman.