The Book Pertaining to Clothes and Decoration (Kitab Al-Libas wa'l-Zinah)
Muslim :: Book 24 : Hadith 5214
Anas b. Malik reported that Allah's Apostle (may peace be upon him) had made for him a silver ring. and got engraved on it (Mubamrnad, Messenger of Allah) and said to the people I have got made a ring of silver and engraved in it (these words) (Mubamrnad, Messenger of Allah). So none should engrave these (words) like this engravement.