Musnad Ahmad 1153:1893

Mu'ammar ibn Sulayman narrated to us, from Khasif, from Mujahid, from Aisha, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) forbade five things: wearing silk, gold, drinking from gold and silver vessels, the red saddle-cloth (maytharah), and wearing Al-Qassi (a type of garment containing silk)." Aisha said: "O Messenger of Allah, what about a small amount of gold used to tie musk or to tie something with?" He said: "No, make it silver and color it with some saffron."