Sahih al-Bukhari 5875

Arabic

حَدَّثَنَا آدَمُ بْنُ أَبِي إِيَاسٍ، حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ ـ رضى الله عنه ـ قَالَ لَمَّا أَرَادَ النَّبِيُّ صلى الله عليه وسلم أَنْ يَكْتُبَ إِلَى الرُّومِ قِيلَ لَهُ إِنَّهُمْ لَنْ يَقْرَءُوا كِتَابَكَ إِذَا لَمْ يَكُنْ مَخْتُومًا‏.‏ فَاتَّخَذَ خَاتَمًا مِنْ فِضَّةٍ، وَنَقْشُهُ مُحَمَّدٌ رَسُولُ اللَّهِ‏.‏ فَكَأَنَّمَا أَنْظُرُ إِلَى بَيَاضِهِ فِي يَدِهِ‏.‏

English translation

Narrated Anas bin Malik:When the Prophet (ﷺ) intended to write to the Byzantines, it was said to him, "Those people do not read your letter unless it is stamped." So the Prophet (ﷺ) took a silver ring and got 'Muhammad, the Apostle of Allah' engraved on it .... as if I am now looking at its glitter in his hand

Reference: Sahih al-Bukhari 5875, Book of Dress. English translation by Dr. Muhammad Muhsin Khan.