ʿAmr bin ʿAbasah reported to me that he heard the Prophet ﷺ say: “The closest that the Lord is to a worshipper is during the last part of the night, so if you are able to be of those who remember Allah in that hour, then do so.”  

سَمِعْتُ أَبَا أُمَامَةَ ؓ يَقُولُ حَدَّثَنِي عَمْرُو بْنُ عَبَسَةَ أَنَّهُ سَمِعَ النَّبِيَّ ﷺ يَقُولُ أَقْرَبُ مَا يَكُونُ الرَّبُّ مِنَ الْعَبْدِ فِي جَوْفِ اللَّيْلِ الآخِرِ فَإِنِ اسْتَطَعْتَ أَنْ تَكُونَ مِمَّنْ يَذْكُرُ اللَّهَ فِي تِلْكَ السَّاعَةِ فَكُنْ قَالَ هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ غَرِيبٌ مِنْ هَذَا الْوَجْهِ  

[Machine] I came to the Messenger of Allah ﷺ while he was descending from 'Ukaz. So I said, "O Messenger of Allah, is there any invocation closer (to Allah) than another, or a time that should be observed, or something that should be mentioned?" He said, "Yes, indeed. The closest that a servant can be to his Lord is during the last third of the night. If you can be among those who remember Allah during that time, then do so."  

أَتَيْتُ رَسُولَ اللَّهِ ﷺ وَهُوَ نَازِلٌ بِعُكَاظٍ فَقُلْتُ يَا رَسُولَ اللَّهِ هَلْ مِنْ دَعْوَةٍ أَقْرَبُ مِنْ أُخْرَى أَوْ سَاعَةٌ تَبْقَى أَوْ يَنْبَغِي ذِكْرُهَا؟ قَالَ «نَعَمْ إِنَّ أَقْرَبَ مَا يَكُونُ الرَّبُّ مِنَ الْعَبْدِ جَوْفُ اللَّيْلِ الْآخِرِ فَإِنِ اسْتَطَعْتَ أَنْ تَكُونَ مِمَّنْ يَذْكُرُ اللَّهَ فِي تِلْكَ السَّاعَةِ فَكُنْ»