Yaseen - 36:69 We have not taught him poetry, nor is it fit for him. This is but a message and a clear Qur´an.
They called Prophet Muhammad a poet who invented the Qur'an:
The Prophets/21:2 Whenever a new message (dhikr) comes to them from their Lord, they listen to it without taking it seriously.
The Prophets/21:3 "Their hearts are reckless. The wrongdoers talked to each other in secret: "Is this man not a man like you? Are you going to be bewitched?"
The Prophets/21:4 "He said, "My Lord knows every word in heaven and earth. He is the Hearing, the Knowing. "
The Prophets/21:5 "They even said, "It is a vain imagination,"and, "He has fabricated it,"and, "He is a poet; let him bring us miracles like the messengers of old."

Those Who Set The Ranks/37:35 "When it was said to them: "La ilaaha illa Allah", they were arrogant."
Those Who Set The Ranks/37:36 "They used to say: "Shall we abandon our gods for a mad poet?"
Those Who Set The Ranks/37:37 Indeed, he has brought the truth and confirmed the messengers.

The Mountain/52:29 You give advice. By the favor of your Lord towards you, you are neither a seer nor a madman.
The Mountain/52:30 "Or do they say, "He is a poet, we are waiting for him to die"?"
The Mountain/52:31 "Say, "Wait; I am waiting with you."

The Sure Truth/69:40 That is the Word (brought) by an honored messenger.
The Sure Truth/69:41 It is not the word of a poet; how little do you believe?
The Sure Truth/69:42 Nor is it the word of a seer; how little do you think?
The Sure Truth/69:43 It is sent down from the Lord of the universes.

Yaseen/36:69 We have not taught him poetry, nor is it fit for him. This is but a message and a clear Qur´an.