A book attributed to the Messenger of Allah

Q: Could you kindly advise whether the attached paper to this letter is authentic or not? May Allah reward you with the best for serving the Muslims. The attached paper is a copy of the letter which is claimed that the Prophet (peace be upon him) sent to Al-Mundhir ibn Sawa.

A: This letter with the wording mentioned was stated by historians, such as Ibn Al-Qayyim in "Zad Al-Ma`ad" (vol. 3, p. 962), Ibn Sayyid Al-Nas in his book "`Uyun Al-Athar," Ibn Al-Athir in "Al-Tarikh," and others. We do not have any evidence to prove that the attached letter was written in the same handwriting which the Prophet (peace be upon him) dictated. (Part No. 3; Page No. 227) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.