Sunan Ibn Majah, Volume 2, Book 5, Hadith 1388 (DarusSalam) ⓘ
It was narrated that ‘Ali bin Abu Talib said: “The Messenger of Allah said: ‘When it is the night of the middle of Sha’ban, spend its night in prayer and observe a fast on that day. For Allah descends at sunset on that night to the lowest heaven and says: ‘Is there no one who will ask Me for forgiveness, that I may forgive him? Is there no one who will ask Me for provision, that I may provide for him? Is there no one who is afflicted by trouble, that I may relieve him?’ And so on, until dawn comes.’”
حَدَّثَنَا الْحَسَنُ بْنُ عَلِيٍّ الْخَلاَّلُ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَنْبَأَنَا ابْنُ أَبِي سَبْرَةَ، عَنْ إِبْرَاهِيمَ بْنِ مُحَمَّدٍ، عَنْ مُعَاوِيَةَ بْنِ عَبْدِ اللَّهِ بْنِ جَعْفَرٍ، عَنْ أَبِيهِ، عَنْ عَلِيِّ بْنِ أَبِي طَالِبٍ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " إِذَا كَانَتْ لَيْلَةُ النِّصْفِ مِنْ شَعْبَانَ فَقُومُوا لَيْلَهَا وَصُومُوا يَوْمَهَا . فَإِنَّ اللَّهَ يَنْزِلُ فِيهَا لِغُرُوبِ الشَّمْسِ إِلَى سَمَاءِ الدُّنْيَا فَيَقُولُ أَلاَ مِنْ مُسْتَغْفِرٍ فَأَغْفِرَ لَهُ أَلاَ مُسْتَرْزِقٌ فَأَرْزُقَهُ أَلاَ مُبْتَلًى فَأُعَافِيَهُ أَلاَ كَذَا أَلاَ كَذَا حَتَّى يَطْلُعَ الْفَجْرُ " .
also referenced under: Hadith 1388 (Reference) & Book 5, Hadith 1451 (In-Book)