Sahih al-Bukhari 6321
Narrated Abu Huraira:
Allah's Messenger (ﷺ) said, "When it is the last third of the night, our Lord, the Blessed, the Superior, 
descends every night to the heaven of the world and says, 'Is there anyone who invokes Me (demand 
anything from Me), that I may respond to his invocation; Is there anyone who asks Me for something 
that I may give (it to) him; Is there anyone who asks My forgiveness that I may forgive him?' "
حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا مَالِكٌ، عَنِ ابْنِ شِهَابٍ، عَنْ أَبِي عَبْدِ اللَّهِ الأَغَرِّ، وَأَبِي، سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏
"‏ يَتَنَزَّلُ رَبُّنَا تَبَارَكَ وَتَعَالَى كُلَّ لَيْلَةٍ إِلَى السَّمَاءِ الدُّنْيَا حِينَ يَبْقَى ثُلُثُ اللَّيْلِ الآخِرُ يَقُولُ مَنْ يَدْعُونِي فَأَسْتَجِيبَ لَهُ، مَنْ يَسْأَلُنِي فَأُعْطِيَهُ، وَمَنْ يَسْتَغْفِرُنِي فَأَغْفِرَ لَهُ?"‏‏‏