'Abdullah bin Az-Zubair said, while he was on the Minbar delivering a Khutbah:"Muhammad [SAW] said: 'Whoever wears silk in this world, will not wear it in the Hereafter.'"
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا حَمَّادٌ، عَنْ ثَابِتٍ، قَالَ سَمِعْتُ عَبْدَ اللَّهِ بْنَ الزُّبَيْرِ، وَهُوَ عَلَى الْمِنْبَرِ يَخْطُبُ وَيَقُولُ قَالَ مُحَمَّدٌ صلى الله عليه وسلم " مَنْ لَبِسَ الْحَرِيرَ فِي الدُّنْيَا فَلَنْ يَلْبَسَهُ فِي الآخِرَةِ " .
Nesai
The Book of Adornment • Hadith 5304