Bara' bin Azib (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) commanded us to do seven things and forbade us seven: he commanded us "to visit the sick, to pray the funeral prayer, to spread the greeting of salam, to accept invitations, to respond to one who sneezes, to help the oppressed, and to keep oaths true; and he forbade us to drink from silver vessels, for whoever drinks from these vessels in this world will not drink from them in the Hereafter; and he forbade gold rings, silk saddle cushions, cloth made of qassi, and wearing thick and fine silk."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الخوف / 6067