Sahih al-Bukhari 5875
Sahih al-Bukhari · Book 77: Dress · Taking a ring for stamping letters
Narrated Anas bin Malik:
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 .
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.