Sunan Abi Dawud, Book 19, Hadith 2993 (USC-MSA) ⓘ

Narrated Yazid ibn Abdullah: We were at Mirbad. A man with dishevelled hair and holding a piece of red skin in his hand came. We said: You appear to be a bedouin. He said: Yes. We said: Give us this piece of skin in your hand. He then gave it to us and we read it. It contained the text: "From Muhammad, Messenger of Allah, to Banu Zuhayr ibn Uqaysh. If you bear witness that there is no god but Allah, and that Muhammad is the Messenger of Allah, offer prayer, pay zakat, pay the fifth from the booty, and the portion of the Prophet and his special portion (safi), you will be under by the protection of Allah and His Apostle." We then asked: Who wrote this document for you? He replied: The Messenger of Allah.

حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا قُرَّةُ، قَالَ سَمِعْتُ يَزِيدَ بْنَ عَبْدِ اللَّهِ، قَالَ كُنَّا بِالْمِرْبَدِ فَجَاءَ رَجُلٌ أَشْعَثُ الرَّأْسِ بِيَدِهِ قِطْعَةُ أَدِيمٍ أَحْمَرَ فَقُلْنَا كَأَنَّكَ مِنْ أَهْلِ الْبَادِيَةِ ‏.‏ فَقَالَ أَجَلْ ‏.‏ قُلْنَا نَاوِلْنَا هَذِهِ الْقِطْعَةَ الأَدِيمَ الَّتِي فِي يَدِكَ فَنَاوَلَنَاهَا فَقَرَأْنَاهَا فَإِذَا فِيهَا ‏ "‏ مِنْ مُحَمَّدٍ رَسُولِ اللَّهِ إِلَى بَنِي زُهَيْرِ بْنِ أُقَيْشٍ إِنَّكُمْ إِنْ شَهِدْتُمْ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَنَّ مُحَمَّدًا رَسُولُ اللَّهِ وَأَقَمْتُمُ الصَّلاَةَ وَآتَيْتُمُ الزَّكَاةَ وَأَدَّيْتُمُ الْخُمُسَ مِنَ الْمَغْنَمِ وَسَهْمَ النَّبِيِّ صلى الله عليه وسلم وَسَهْمَ الصَّفِيِّ أَنْتُمْ آمِنُونَ بِأَمَانِ اللَّهِ وَرَسُولِهِ ‏" ‏ ‏.‏ فَقُلْنَا مَنْ كَتَبَ لَكَ هَذَا الْكِتَابَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏.‏