Musnad Ahmad 27:266

Yahya narrated to us, from Ubaydullah, Nafi’ informed me, from Ibn Umar, that Umar saw a garment of silk-mixed fabric (sira') or silk being sold. He said to the Prophet, peace and blessings of Allah be upon him: "If you were to buy this to wear on Friday or for the delegations?" He said: "Indeed, only he who has no share (in the Hereafter) wears this." He said: Then some of these garments were gifted to the Messenger of Allah, peace and blessings of Allah be upon him, and he sent one of them to Umar. He said: "I heard you say what you said, yet you sent it to me?" He said: "I only sent it to you so that you may sell it or clothe someone else with it."