Who said: "I have brought you a people who love death as much as you love life"?

The speaker of the statement is Khalid ibn al-Walid, may Allah be pleased with him. He wrote to the King of Persia: "In the name of Allah, the Most Gracious, the Most Mercinful. From Khalid ibn al-Walid to the kings of Persia. All praise is due to Allah, who has disbanded your system, weakened your cunning, and scattered your unity... So embrace Islam, or else pay the jizya. If not, then I have brought you a people who love death as much as you love life."