When the Prophet ﷺ intended to write to the Byzantines, the people said, "They do not read a letter unless it is sealed (stamped)." Therefore the Prophet ﷺ took a silver ring----as if I am looking at its glitter now----and its engraving was: 'Muhammad, Apostle of Allah'.  

لَمَّا أَرَادَ النَّبِيُّ ﷺ أَنْ يَكْتُبَ إِلَى الرُّومِ قَالُوا إِنَّهُمْ لاَ يَقْرَءُونَ كِتَابًا إِلاَّ مَخْتُومًا فَاتَّخَذَ النَّبِيُّ ﷺ خَاتَمًا مِنْ فِضَّةٍ كَأَنِّي أَنْظُرُ إِلَى وَبِيصِهِ وَنَقْشُهُ مُحَمَّدٌ رَسُولُ اللَّهِ  

"The Messenger of Allah [SAW] wanted to write to the Romans, and they (the Companions) said: 'They do not read any letter unless it has a seal.' So he took a ring of silver and it is as if I can see its whiteness on his hand, and engraved on it (were the words): 'Muhammad Rasul Allah.'"  

أَرَادَ رَسُولُ اللَّهِ ﷺ أَنْ يَكْتُبَ إِلَى الرُّومِ فَقَالُوا إِنَّهُمْ لاَ يَقْرَءُونَ كِتَابًا إِلاَّ مَخْتُومًا فَاتَّخَذَ خَاتَمًا مِنْ فِضَّةٍ كَأَنِّي أَنْظُرُ إِلَى بَيَاضِهِ فِي يَدِهِ وَنُقِشَ فِيهِ مُحَمَّدٌ رَسُولُ اللَّهِ  

"The Messenger of Allah [SAW] wanted to write to the Romans, but they (the Companions) said: 'They do not read any letter unless it has a seal.' So he took a ring of silver, and it is as if I can see its whiteness on his hand, and on it were engraved (the words): "Muhammad Rasul Allah (Muhammad the Messenger of Allah)."  

أَرَادَ رَسُولُ اللَّهِ ﷺ أَنْ يَكْتُبَ إِلَى الرُّومِ فَقَالُوا إِنَّهُمْ لاَ يَقْرَءُونَ كِتَابًا إِلاَّ مَخْتُومًا فَاتَّخَذَ خَاتَمًا مِنْ فِضَّةٍ كَأَنِّي أَنْظُرُ إِلَى بَيَاضِهِ فِي يَدِهِ وَنُقِشَ فِيهِ مُحَمَّدٌ رَسُولُ اللَّهِ  

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."  

أَرَادَ رَسُولُ اللَّهِ ﷺ أَنْ يَكْتُبَ إِلَى بَعْضِ الأَعَاجِمِ فَقِيلَ لَهُ إِنَّهُمْ لاَ يَقْرَءُونَ كِتَابًا إِلاَّ بِخَاتَمٍ فَاتَّخَذَ خَاتَمًا مِنْ فِضَّةٍ وَنَقَشَ فِيهِ مُحَمَّدٌ رَسُولُ اللَّهِ  

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." (Using translation from Abū Dāʾūd 4214)   

أَنَّ رَسُولَ اللهِ ﷺ أَرَادَ أَنْ يَكْتُبَ إِلَى الْأَعَاجِمِ فَقِيلَ إِنَّهُمْ لَا يَقْبَلُونَ كِتَابًا إِلَّا بِنَقْشٍ فَاتَّخَذَ رَسُولُ اللهِ ﷺ خَاتَمًا مِنْ فِضَّةٍ وَنَقَشَ فِيهِ مُحَمَّدٌ رَسُولُ اللهِ  

[Machine] The Messenger of Allah ﷺ wanted to write to the non-Arabs, so they told him that they only read a book that has a seal with an inscription. So the Messenger of Allah ﷺ ordered a silver seal to be made and inscribed on it "Muhammad, Messenger of Allah."  

أَنَّ رَسُولَ اللَّهِ ﷺ أَرَادَ أَنْ يَكْتُبَ إِلَى الْأَعَاجِمِ فَقَالُوا لَهُ أَنَّهُمْ لَا يَقْرَءُونَ كِتَابًا إِلَّا بِخَاتَمٍ فِيهِ نَقْشٌ فَأَمَرَ رَسُولُ اللَّهِ ﷺ بِخَاتَمٍ فِضَّةٍ فَنَقَشَ فِيهِ «مُحَمَّدٌ رَسُولُ اللَّهِ»  

"The Messenger of Allah [SAW] wanted to write to the Romans, but they (the Companions) said: 'They do not read any letter unless it has a seal.' So he took a ring of silver, and it is as if I can see its whiteness on his hand, and on it were engraved (the words): "Muhammad Rasul Allah (Muhammad the Messenger of Allah)." (Using translation from Nasāʾī 5201)  

أَرَادَ رَسُولُ اللهِ ﷺ أَنْ يَكْتُبَ إِلَى الرُّومِ فَقَالُوا «إِنَّهُمْ لَا يَقْرَءُونَ كِتَابًا إِلَّا مَخْتُومًا فَاتَّخَذَ خَاتَمًا مِنْ فِضَّةٍ كَأَنِّي أَنْظُرُ إِلَى بَيَاضِهِ فِي يَدِهِ وَنَقَشَ فِيهِ مُحَمَّدٌ رَسُولُ اللهِ»  

"The Messenger of Allah [SAW] wanted to write to the Romans, but they (the Companions) said: 'They do not read any letter unless it has a seal.' So he took a ring of silver, and it is as if I can see its whiteness on his hand, and on it were engraved (the words): "Muhammad Rasul Allah (Muhammad the Messenger of Allah)." (Using translation from Nasāʾī 5201)  

أَرَادَ رَسُولُ اللهِ ﷺ أَنْ يَكْتُبَ كِتَابًا إِلَى الرُّومِ فَقَالُوا «إِنَّهُمْ لَا يَقْرَءُونَ كِتَابًا إِلَّا مَخْتُومًا فَاتَّخَذَ خَاتَمًا مِنْ فِضَّةٍ كَأَنِّي أَنْظُرُ إِلَى بَيَاضِهِ فِي يَدِهِ وَنَقَشَ فِيهِ مُحَمَّدٌ رَسُولُ اللهِ»  

Anas b. Malik reported that when Messenger of Allah ﷺ decided to write letters to the Byzantine (Emperor) they (his Companions) told him that they would not read a letter unless it is sealed. (Then) Messenger of Allah ﷺ had a silver ring made (for himself), (its shape is so vivid in my mind) as if I see its brightness in the band of Messenger of Allah ﷺ and its engravement was (Muhammad, Messenger of Allah). (Using translation from Muslim 2092c)  

أَرَادَ رَسُولُ اللهِ ﷺ أَنْ يَكْتُبَ إِلَى الرُّومِ فَقَالُوا إِنَّهُمْ لَا يَقْرَءُونَ كِتَابًا إِلَّا مَخْتُومًا قَالَ فَاتَّخَذَ خَاتَمًا مِنْ فِضَّةٍ كَأَنِّي أَنْظُرُ إِلَى بَيَاضِهِ فِي يَدِهِ وَنُقِشَ فِيهِ مُحَمَّدٌ رَسُولُ اللهِ