The Holy Koran is sent by the Lord of all the worlds 10:37-40
10:37 This Koran could not have been forged by other than Allah. It confirms what was before it; a distinguishing Book, in which there is no doubt, from the Lord of all the worlds.
10:38 Do they say (the unbelievers), 'He has forged it'. Say, 'Compose one chapter like it, and call upon whom you will, other than Allah (to help you), if what you say is true! '
10:39 They have belied that which they did not understand of its knowledge, nor has its interpretation reached them. Those who were before also belied. But see how was the end of the harm doers.