The One Covering Himself - 73:5 We will leave you a weighty word.
In the context of verses 1, 2...7: Remembering Allah at night and thinking:
The Companies/39:9 "What do you say to one who prostrates himself at night and stands up and meditates and is conscious of the Hereafter and hopes for the mercy of his Lord? Say, "Are those who know and those who do not know the same?"Only those who have understanding take admonition."
اَمَّنْ هُوَ قَانِتٌ اٰنَٓاءَ الَّيْلِ سَاجِداً وَقَٓائِماً يَحْذَرُ الْاٰخِرَةَ وَيَرْجُوا رَحْمَةَ رَبِّه۪ۜ قُلْ هَلْ يَسْتَوِي الَّذ۪ينَ يَعْلَمُونَ وَالَّذ۪ينَ لَا يَعْلَمُونَۜ اِنَّمَا يَتَذَكَّرُ اُو۬لُوا الْاَلْبَابِ۟

The Night Journey/17:79 And as an extra good deed, meditate at night so that your Lord may raise you to an honorable station.
وَمِنَ الَّيْلِ فَـتَهَجَّدْ بِه۪ نَافِلَةً لَكَۗ عَسٰٓى اَنْ يَبْعَثَكَ رَبُّكَ مَقَاماً مَحْمُوداً

The Criterion/25:64 They prostrate themselves to their Lord in the solitude of the night, and they meditate.
وَالَّذ۪ينَ يَب۪يتُونَ لِرَبِّهِمْ سُجَّداً وَقِيَاماً

The Romans/30:17 So praise Allah when you retire at night and when you rise in the morning.
فَسُبْحَانَ اللّٰهِ ح۪ينَ تُمْسُونَ وَح۪ينَ تُصْبِحُونَ

The Mountain/52:49 Glorify Him at night and when the stars disappear.
وَمِنَ الَّيْلِ فَسَبِّحْهُ وَاِدْبَارَ النُّجُومِ

The One Covering Himself/73:3 Halfway or a little before halfway.
نِصْفَهُٓ اَوِ انْقُصْ مِنْهُ قَل۪يلاًۙ
The One Covering Himself/73:4 Or a little after half. Read the Qur´an carefully and thoughtfully.
اَوْ زِدْ عَلَيْهِ وَرَتِّلِ الْقُرْاٰنَ تَرْت۪يلاًۜ
The One Covering Himself/73:5 We will leave you a weighty word.
اِنَّا سَنُلْق۪ي عَلَيْكَ قَوْلاً ثَق۪يلاًۜ
The One Covering Himself/73:6 Surely the construction of ideas at night is more effective and more expressive.
اِنَّ نَاشِئَةَ الَّيْلِ هِيَ اَشَدُّ وَطْـٔاً وَاَقْوَمُ ق۪يلاًۜ
The One Covering Himself/73:20 Your Lord knows that you and a group of your companions get up less than two-thirds, half and one-third of the night. Allah determines the amount of the night and the day. He has forgiven you because He knows that you cannot do it. So read from the Qur´an as much as is easy for you. He knows that among you are the sick, those who seek sustenance from the bounty of Allah in the earth, and those who fight in the way of Allah. Read from it as much as is easy for you. Observe the prayer, pay the zakat, and make a debt to Allah through good deeds. Whatever good you do for yourselves you will find a better and greater reward in the sight of Allah. Seek forgiveness from Allah; Allah is Forgiving, Merciful.
اِنَّ رَبَّكَ يَعْلَمُ اَنَّكَ تَقُومُ اَدْنٰى مِنْ ثُلُثَيِ الَّيْلِ وَنِصْفَهُ وَثُلُثَهُ وَطَٓائِفَةٌ مِنَ الَّذ۪ينَ مَعَكَۜ وَاللّٰهُ يُقَدِّرُ الَّيْلَ وَالنَّهَارَۜ عَلِمَ اَنْ لَنْ تُحْصُوهُ فَتَابَ عَلَيْكُمْ فَاقْرَؤُ۫ا مَا تَيَسَّرَ مِنَ الْقُرْاٰنِۜ عَلِمَ اَنْ سَيَكُونُ مِنْكُمْ مَرْضٰىۙ وَاٰخَرُونَ يَضْرِبُونَ فِي الْاَرْضِ يَبْتَغُونَ مِنْ فَضْلِ اللّٰهِۙ وَاٰخَرُونَ يُقَاتِلُونَ ف۪ي سَب۪يلِ اللّٰهِۘ فَاقْرَؤُ۫ا مَا تَيَسَّرَ مِنْهُۙ وَاَق۪يمُوا الصَّلٰوةَ وَاٰتُوا الزَّكٰوةَ وَاَقْرِضُوا اللّٰهَ قَرْضاً حَسَناًۜ وَمَا تُقَدِّمُوا لِاَنْفُسِكُمْ مِنْ خَيْرٍ تَجِدُوهُ عِنْدَ اللّٰهِ هُوَ خَيْراً وَاَعْظَمَ اَجْراًۜ وَاسْتَغْفِرُوا اللّٰهَۜ اِنَّ اللّٰهَ غَفُورٌ رَح۪يمٌ

The Man/76:26 Prostrate to Him at night and glorify Him in the long nights.
وَمِنَ الَّيْلِ فَاسْجُدْ لَهُ وَسَبِّحْهُ لَيْلاً طَو۪يلاً


The Letter Qaf/50:40 Glorify Him at night and after the prostrations.
وَمِنَ الَّيْلِ فَسَبِّحْهُ وَاَدْبَارَ السُّجُودِ