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 ﷺ, 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 ﷺ and his special portion (safi), you will be under by the protection of Allah and His Messenger. " We then asked: Who wrote this document for you? He replied: The Messenger of Allah ﷺ.
Hadith Referenceسنن ابي داود / كتاب الخراج والفيء والإمارة / 2999
Hadith Gradingالألبانی:صحيح الإسناد | زبیر علی زئی:صحيح, الصحابي اسمه النمر بن تولب الشاعر
Hadith Takhrij« تفرد بہ أبوداود، (تحفة الأشراف: 15683)، وقد أخرجہ: مسند احمد (5/77، 78، 363) (صحیح الإسناد) »
´It was narrated that Yazid bin Ash-Shikhkhir said:` "While I was with Mutarrif in Al-Mirbad, a man came in carrying a piece of leather and said: 'This was written to me by the Messenger of Allah. Is there anyone among you who can read?' I said: 'I can read.' And it was (a letter) from Muhammad the Prophet to Banu Zuhair bin Uqaish, who had testified to Lailah illallah, and that Muhammad is the Messenger of Allah, and had left the idolaters, and had agreed to give the Khumus from their spoils of the Prophet, and wheatever he chose for himself, so they became safe and secure by the covenant of Allah and His Messenger."
Hafiz Muhammad Ameen
The correct view is that both the general and specific shares of the Noble Prophet (sallallahu alayhi wa sallam) are included in the khums, even though the apparent wording of the issues regarding the distribution of war booty (mal-e-ghanīmah) and fay’ property (mal-e-fay’) seems to indicate that these shares are separate from the khums. However, it is also necessary to take other narrations into consideration. (See Fawa’id, Hadith: 4143, 4144)
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 4151