"When the Prophet of Allah (ﷺ) wanted to write to the foreigners, it was said to him: 'The foreigners do not accept a letter unless it has a seal.' So he had a ring made." He said: "It is as if I am now looking at its whiteness in his hand."
Jami` at-Tirmidhi Book 42, Hadith 31
← Previous Hadith that Abu Sufyan bin Harb informed him that Hiraql had sent for him while he was with a party of the Quraish, and they were trading in Ash-Sham, so they went to him." And he mentioned the Hadith and said: "Then he called for the letter of the Messenger of Allah (ﷺ) to be read, and it said in it: 'In the Name of Allah, the Merciful, the Beneficent. From Muhammad, Allah's Slave and His Messenger, to Hiraql the leader of Rome. Peace be upon whoever follows the guidance. To proceed:"

Jami` at-Tirmidhi Book 42, Hadith 30 Next Hadith → "Two of my companions and I went and presented ourselves to the Companions of the Prophet (ﷺ), for our hearing and sight had gone from suffering (hunger and thirst). But there was no one who would accept us. So we went to the Prophet (ﷺ) and he brought us to his family where there were three goats. The Prophet (ﷺ) said: 'Milk these.' We milked them, and each person drank his share, and we put aside a share for the Messenger of Allah (ﷺ). The Messenger of Allah (ﷺ) came during the night and gave the Salam such that it would not wake the sleeping person, and the one who was awake could hear it. Then he went to the Masjid to per form Salat. Then he went for his drink and drank it."

Jami` at-Tirmidhi Book 42, Hadith 32