Musannaf Ibn Abi Shayba 16:428

Abu Bakr narrated to us, he said: Ubaydah ibn Sa'id narrated to us, from Shu'bah, from Khalifah ibn Ka'b, that he said: I heard Abdullah ibn al-Zubayr delivering a sermon. He said: "Beware, do not clothe your women in silk, for I heard Umar ibn al-Khattab saying: The Messenger of Allah (ﷺ) said: 'Do not wear silk, for whoever wears it in this world will not wear it in the Hereafter.'"