What is the significance of the ring the Prophet Muhammad (saw) wore according to the hadith narrated by Anas?
 Narrated Humaid:                     Anas was asked, "Did Allah's Apostle wear a ring?" He said, "Yes. Once he delayed the `Isha' prayer till midnight and after the prayer, he faced us and said, 'The people prayed and have slept and you remained in prayer as long as you waited for it.' " Anas added, "As if I were just now observing the glitter of his ring."