The Cattle - 6:91
"They did not appreciate Allah properly when they said: "Allah does not send down anything to any man". Say: "Who sent down the Book which Moses brought as a guidance and light for the people, which you wrote on paper to show them, but you concealed most of it. Through it you have learned what you and your fathers did not know?"Say: "Allah"and leave them in the error into which they have plunged, and let them play."
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."