question #3 Sahih al-Bukhari 5873, Book 77, Hadith 90 : What was engraved on the Prophet Muhammad’s silver ring and what does it signify?

Allah’s Messenger (ﷺ) had a silver ring made for himself and it was worn by him on his hand. Afterwards it
was worn by Abu Bakr, and then by `Umar, and then by `Uthman till it fell in the Aris well. (On that
ring) was engraved: ‘Muhammad, the Messenger of Allah.”