Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Aamir (may Allah be pleased with him) that Hazrat Khalid bin Waleed (may Allah be pleased with him) wrote a letter from the place of Heerah to the Marzban of Persia as follows: In the name of Allah, the Most Gracious, the Most Merciful. From Khalid bin Waleed to the Marzban of Persia. Peace be upon him who follows guidance.