Submit to Islam and be safe. Or agree to the payment of the Jizya (tax), and you and your people will be under our protection, else you will have only yourself to blame for the consequences, for I bring the men who desire death as ardently as you desire life.
Khalid ibn al-Walid's letter to the Persian monarch Emperor Yazdegerd III, as quoted in John Clark Ridpath "History of the World, Volume IV (Book XII: The Mohammedan Ascendency, p. 463), 1910.
