Significance of qiyam al-layal in the last third of the night

that the Messenger of Allah ﷺ said, "Our Lord, the Blessed, the All High, comes every night down on the nearest Sky when the last third of the night remains, saying: ’Is there anyone to invoke Me, so that I may respond to [his invocation]? Is there anyone to ask Me, so that I may grant him [his request]? Is there anyone seeking My forgiveness, so that I may forgive him?’”  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ: «يَنْزِلُ رَبُّنَا تَبَارَكَ وَتَعَالَى كُلَّ لَيْلَةٍ إِلَى السَّمَاءِ الدُّنْيَا حِينَ يَبْقَى ثُلُثُ اللَّيْلِ الآخِرُ يَقُولُ: مَنْ يَدْعُونِي فَأَسْتَجِيبَ لَهُ؟ مَنْ يَسْأَلُنِي فَأُعْطِيَهُ؟ مَنْ يَسْتَغْفِرُنِي فَأَغْفِرَ لَهُ؟»