Sahih Muslim | Book 24 | Hadith Number 5214

Narrated by Anas b. Malik
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 (Muhammad, Messenger of Allah) and said to the people I have got made a ring of silver and engraved in it (these words) (Muhammad, Messenger of Allah). So none should engrave these (words) like this engravement.