Jami` at-Tirmidhi 1747
جامع الترمذي#1747SahihNarrated Anas bin Malik:"The inscription on the ring of the Prophet (ﷺ) was in three lines: 'Muhammad' on a line, 'Messenger' on a line, and 'Allah' on a line
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Zubair Ali ZaiSahih Bukhari
In-book reference: 24:28