Musnad Ahmad 32:1875

'Affan narrated to us, Hammad bin Salamah narrated to us, he said: Thabit informed us that they asked Anas bin Malik: "Did the Messenger of Allah, peace and blessings of Allah be upon him, have a ring?" He said: "Yes." Then he said: "The Messenger of Allah, peace and blessings of Allah be upon him, delayed the night prayer (Isha) one night until nearly half the night had passed. Then he said: 'Indeed, the people have prayed and slept, and you have remained in prayer as long as you were waiting for the prayer.'" Anas said: "And it is as if I am looking at the glitter of his ring," and he raised his left hand.