The Jinns stealing Information from the Sky before the the Messenger ﷺ was sent and striking Them with flaming Fire after His Coming.

Allah informs about the Jinns when He sent His Messenger Muhammad ﷺ and revealed the Qur'an to him. Among the ways He protected it (the Qur'an) was by filling sky with stern guards guarding it from all of its sides. The devils were then expelled from the places where they used to sit prior to that. This was so that they could not steal anything from the Qur'an and tell it to the soothsayers, thereby causing matters to be confused and mixed up. If this happened it would not be known who was being truthful. Allah did this out of His kindness to His creation, His mercy upon His servants and His protection of His Mighty Book (the Qur'an). This is why the Jinns said,

وَأَنَّا لَمَسْنَا السَّمَآءَ فَوَجَدْنَـهَا مُلِئَتْ حَرَساً شَدِيداً وَشُهُباً - وَأَنَّا كُنَّا نَقْعُدُ مِنْهَا مَقَـعِدَ لِلسَّمْعِ فَمَن يَسْتَمِعِ الاٌّنَ يَجِدْ لَهُ شِهَاباً رَّصَداً

وَأَنَّا لَمَسْنَا السَّمَاءَ فَوَجَدْنَاهَا مُلِئَتْ حَرَ‌سًا شَدِيدًا وَشُهُبًا (...and that we sought [ to reach ] the sky, but we found it filled with stern guards and flames....72:8). The word sama' is used in two different senses: 'sky' as well as 'cloud'. It would appear that here the word is used in the latter sense.

The Jinn Used to Go only up to the Clouds to Eavesdrop, Not to the Sky