Prophet Jonah - 10:2
"To a man from among them: "Warn the people and give glad tidings to the believers that they have a favored place with their Lord"? The disbelievers said, "This is a clear sorcerer."
Why a human messenger?
The Night Journey/17:95
"Say: "If there were angels inhabiting the earth, We would have sent to them an angel from heaven as a messenger."