It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him), he says: When the Messenger of Allah (peace and blessings be upon him) intended to write letters to the rulers of non-Arabs, it was said to him that the rulers of non-Arabs do not accept letters that are not sealed. So the Messenger of Allah (peace and blessings be upon him) had a ring made. It is as if I am still seeing its whiteness in the blessed palm of the Prophet (peace and blessings be upon him).
Hadith Referenceشمائل ترمذي / باب ما جاء فى ذكر خاتم رسول الله صلى الله عليه وسلم / 89
Hadith Gradingزبیر علی زئی:صحيح
Hadith Takhrij{ «صحيح» } : « (سنن ترمذي:2718 وقال:هذا حديث حسن صحيح)، صحيح مسلم (2092) من حديث معاذ بن هشام وصحيح بخاري (65) من حديث قتادة به.»