Sahih Bukhari Volume 7, Book 72, Hadith Number 758.

Narrated By Humaid : Anas was asked, “Did the Prophet wear a ring?” Anas said, “Once he delayed the: ‘Isha’ prayer till midnight. Then he came, facing us… as if l am now Looking at the glitter of his ring… and said, “The people have offered their prayers and slept but you have been in prayer as you have been waiting for it.”