Sahih Bukhari Volume 9, Book 97, Hadith 7496

حَدَّثَنَا إِسْمَاعِيلُ، حَدَّثَنِي مَالِكٌ، عَنِ ابْنِ شِهَابٍ، عَنْ أَبِي عَبْدِ اللَّهِ الأَغَرِّ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ يَتَنَزَّلُ رَبُّنَا تَبَارَكَ وَتَعَالَى كُلَّ لَيْلَةٍ إِلَى السَّمَاءِ الدُّنْيَا حِينَ يَبْقَى ثُلُثُ اللَّيْلِ الآخِرُ فَيَقُولُ مَنْ يَدْعُونِي فَأَسْتَجِيبَ لَهُ، مَنْ يَسْأَلُنِي فَأُعْطِيَهُ، مَنْ يَسْتَغْفِرُنِي فَأَغْفِرَ لَهُ ‏"

Narrated By Abu Huraira : Allah's Apostle said, "Every night when it is the last third of the night, our Lord, the Superior, the Blessed, descends to the nearest heaven and says: Is there anyone to invoke Me that I may respond to his invocation? Is there anyone to ask Me so that I may grant him his request? Is there anyone asking My forgiveness so that I may forgive him?."