And we have sought [to reach] the heaven but found it filled with powerful guards and burning flames.
The Saheeh International Quran Translation
وَأَنَّا لَمَسْنَا ٱلسَّمَآءَ فَوَجَدْنَٰهَا مُلِئَتْ حَرَسًا شَدِيدًا وَشُهُبًاAnd we have sought [to reach] the heaven but found it filled with powerful guards and burning flames.