It is reported that Zayd ibn Thabit wrote this letter:
"In the Name of Allah, the All-Merciful, Most Merciful. To the slave of Allah, Mu'awiya, the Amir al-Mu'minin, from Zayd ibn Thabit. Peace be upon you, Amir al-Mu'minin, and the mercy of Allah. I praise Allah to you. There is no god but Him. Following on from that'"
Reference: Al-Adab Al-Mufrad 1122 In-book : Book 45, Hadith 6 English translation : Book 45, Hadith 1122
Help us gift a modern, ad-free Islamic application for the Muslim Ummah. Your donation will be recorded as Sadaqah Jariyah in your book of deeds, In Sha Allah.