(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." (TR)
Reference (TR): Sunan Abi Dawud 4214 (TR)
In-book reference (TR): Book 36, Hadith 1 (TR)
English translation (TR): Book 35, Hadith 4202 (TR)