'Abdullah ibn 'Abbas related that Abu Sufyan ibn Harb sent him
to Heraclius, the Byzantine Emperor, and he called for the letter of the
Messenger of Allah which Dihya had brought to the governor of Busra, who
in turn passed it on to Heraclius. He read it out, saying, 'In the name
of Allah, the Merciful, the Compassionate, from Muhammad, the slave of
Allah and His Messenger, to Heraclius, ruler of the Byzantines. Peace be
upon the one who follows guidance. I call you to Islam. If you become Muslim,
you will be safe and Allah will double your reward. If you turn away, then
you incur the wrong action of your subjects. "O People of the Book!
Come to a proposition which is the same for us and you (to His
words) Bear witness that we are Muslims."
(3:54)'"