Surah At-Tur, Verse 38

أَمۡ لَهُمۡ سُلَّمٞ يَسۡتَمِعُونَ فِيهِۖ فَلۡيَأۡتِ مُسۡتَمِعُهُم بِسُلۡطَٰنٖ مُّبِينٍ٣٨

am lahum sullamun yastamiʿūna fīhi falyati mus'tamiʿuhum bisul'ṭānin mubīnin

Or have they a stairway [into the heaven] upon which they listen? Then let their listener produce a clear authority [i.e., proof].