Ibn 'Abbâs (may Allah be pleased with him) begins with the sky: a barrier was set between the devils and heaven's news.
And flames were sent upon them. It began, Ibn 'Abbâs says, when the Messenger of Allah ﷺ was sent.
Before, he says, they would catch a word of heaven and add nine lies to it. The word was true; the rest was false.
And we sought the heaven, and found it filled with powerful guards and burning flames.
And we used to sit there in places to listen; but whoever listens now finds a flame lying in wait for him.
The Qur'an lets the jinn say it themselves. The same closed sky, in their own words.
The devils went back to their people. “What is wrong with you?” “Something now stands between us and heaven's news.”
“Only something new could have done that. Go east and west, and find what has come between you and the news of heaven.”
Those who went towards Tihâma came upon the Prophet ﷺ at Nakhla. He was on his way to the market of 'Ukâz.
He was leading his companions in the dawn prayer. When they heard the Qur'an, they listened to it.
They said: “This, by Allah, is what has come between you and the news of heaven.”
Ibn 'Abbâs says it plainly: the Messenger of Allah ﷺ did not recite to the jinn, nor see them.
Say: it has been revealed to me that a group of the jinn listened, and said: “We have heard an amazing Qur'an,
it guides to the right course, so we have believed in it, and we will never associate anyone with our Lord.”
Ibn 'Abbâs ends: Allah then revealed “Say: it has been revealed to me”. What was revealed to him ﷺ was the jinn's words.
When was it? The biographers place this dawn on the way back from Tâ'if, after a whole town had refused him.
A town had just shut its doors to him. The same road gave him listeners he could not see.
Why close the sky? Ibn Kathîr answers: so that nothing of the Qur'an could be snatched and put on a soothsayer's tongue.
One dawn, on a road between Mecca and Tâ'if, the Prophet ﷺ led his companions in prayer.
He did not know it yet: someone else was listening.
The sky closed above them, and they went searching. What they found was a man praying at dawn.
Tonight, pray two rak'a and recite slowly, aloud, as if someone you cannot see were listening.