Musnad Abu Ya'la al-Mawsili 167:13

Ishaq narrated to us, Hammad bin Zayd narrated to us, from Hisham, from Hafsa bint Sirin, from Abu Dhibyan, who said: I heard Ibn al-Zubayr while he was delivering a sermon, and he said: Muhammad, peace be upon him, said: "Whoever wears silk in this world will not wear it in the Hereafter." Ibn Umar was at his side, and he said: "Then, by Allah, he will not enter Paradise, for Allah says: 'And their garments therein will be silk.'"