Sahih Muslim 757
Sahih Muslim · Book 6: The Book of Prayer - Travellers · In the night there is an hour when supplications are answered
Jabir reported:
وَحَدَّثَنِي سَلَمَةُ بْنُ شَبِيبٍ ، حَدَّثَنَا الْحَسَنُ بْنُ أَعْيَنَ ، حَدَّثَنَا مَعْقِلٌ ، عَنْ أَبِي الزُّبَيْرِ ، عَنْ جَابِرٍ ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِنَّ مِنَ اللَّيْلِ سَاعَةً لاَ يُوَافِقُهَا عَبْدٌ مُسْلِمٌ يَسْأَلُ اللَّهَ خَيْرًا إِلاَّ أَعْطَاهُ إِيَّاهُ " .
I heard the Messenger of Allah (ﷺ) as saying: There is an hour during the night in which no Muslim bondman will ask Allah for good in this world and the next but He will grant it to him.