Sahih Muslim 1773
The Book of Prayer - Travellers
وَحَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا يَعْقُوبُ، - وَهُوَ ابْنُ عَبْدِ الرَّحْمَنِ الْقَارِيُّ - عَنْ سُهَيْلِ بْنِ أَبِي صَالِحٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ " يَنْزِلُ اللَّهُ إِلَى السَّمَاءِ الدُّنْيَا كُلَّ لَيْلَةٍ حِينَ يَمْضِي ثُلُثُ اللَّيْلِ الأَوَّلُ فَيَقُولُ أَنَا الْمَلِكُ أَنَا الْمَلِكُ مَنْ ذَا الَّذِي يَدْعُونِي فَأَسْتَجِيبَ لَهُ مَنْ ذَا الَّذِي يَسْأَلُنِي فَأُعْطِيَهُ مَنْ ذَا الَّذِي يَسْتَغْفِرُنِي فَأَغْفِرَ لَهُ فَلاَ يَزَالُ كَذَلِكَ حَتَّى يُضِيءَ الْفَجْرُ " .
Abu Huraira reported Allah's Messenger (ﷺ) as saying:Allah descends every night to the lowest heaven when one-third of the first part of the night is over and says: I am the Lord; I am the Lord: who is there to supplicate Me so that I answer him? Who is there to beg of Me so that I grant him? Who is there to beg forgiveness from Me so that I forgive him? He continues like this till the day breaks
Text from the public-domain hadith-api dataset. Numbering follows that dataset and can differ by a few from some printed editions — check the wording, not only the number.