 He summoned his companions and announced that he wanted to write a will, he asked for writing materials to write a statement that would "prevent the Muslim nation from going astray for ever".The first person to reply was Umar, answering that there was no need for any will, arguing that Muhammad was ill and that Umar had the Qur'an which was sufficient for him.Muhammad had earlier sent an expedition against the Byzantine Empire (Roman) that resulted in what was known as the Battle of Mut'ah.