Musannaf Ibn Abi Shayba 16:413

Abu Bakr narrated to us, he said: Isma'il bin 'Ulayyah narrated to us, from 'Abd al-'Aziz bin Suhayb, from Anas, he said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Whoever wears silk in the world will not wear it in the Hereafter."