(1) باب مَا جَاءَ فِي اتِّخَاذِ الْخَاتَمِ
Narrated Anas bin Malik:
The Messenger of Allah (ﷺ) wanted to write to some persian rulers. He was told that they would not read a letter without a seal in the form of a silver ring on which he engraved "Muhammad the Messenger of Allah." (DE)
Reference (DE): Sunan Abi Dawud 4214 (DE)
In-book reference (DE): Book 36, Hadith 1 (DE)
English translation (DE): Book 35, Hadith 4202 (DE)