At the time of difficulty when sleeping: Zaid bin Thaabit (RA) complained to Rasulallah (Sallallahu Alaihi Wasallam) of not being able to go to sleep at times and he advised him to recite the following dua: اللَّهُمَّ غَارَتِ النُّجُومُ وَهَدَأَتِ الْعُيُونُ وَأَنْتَ حَيٌّ قَيُّومٌ * لَا تَأْخُذُكَ سِنَةٌ وَلَا نَوْمٌ يَا حَيُّ يَا قَيُّومُ أَهْدِئْ لَيْلِي وَأَنِمْ عَيْنِي Oh Allah the stars have sunk in and the eyes have become tranquil and quite and You are alive and ever lasting neither does sleep overcome You. Oh the living and ever lasting one make my night my tranquil and give my eyes sleep. (Ibn Sunni, Hisnul Hasin)