The Quran root ل ي ل l-y-l

إِنَّ فِي خَلْقِ السَّمَاوَاتِ وَالْأَرْضِ وَاخْتِلَافِ اللَّيْلِ وَالنَّهَارِ وَالْفُلْكِ الَّتِي تَجْرِي فِي الْبَحْرِ بِمَا يَنفَعُ النَّاسَ وَمَا أَنزَلَ اللَّهُ مِنَ السَّمَاءِ مِن مَّاءٍ فَأَحْيَا بِهِ الْأَرْضَ بَعْدَ مَوْتِهَا وَبَثَّ فِيهَا مِن كُلِّ دَابَّةٍ وَتَصْرِيفِ الرِّيَاحِ وَالسَّحَابِ الْمُسَخَّرِ بَيْنَ السَّمَاءِ وَالْأَرْضِ لَآيَاتٍ لِّقَوْمٍ يَعْقِلُونَ ١٦٤

اللَّيْلِ al-layli · of the night

Indeed, in the creation of the heavens and the earth, and the alternation of the night and the day, and the [great] ships which sail through the sea with that which benefits people, and what Allāh has sent down from the heavens of rain, giving life thereby to the earth after its lifelessness and dispersing therein every [kind of] moving creature, and [His] directing of the winds and the clouds controlled between the heaven and earth are signs for a people who use reason. (Surah Al-Baqarah, 2:164)

أُحِلَّ لَكُمْ لَيْلَةَ الصِّيَامِ الرَّفَثُ إِلَىٰ نِسَائِكُمْ هُنَّ لِبَاسٌ لَّكُمْ وَأَنتُمْ لِبَاسٌ لَّهُنَّ عَلِمَ اللَّهُ أَنَّكُمْ كُنتُمْ تَخْتَانُونَ أَنفُسَكُمْ فَتَابَ عَلَيْكُمْ وَعَفَا عَنكُمْ فَالْآنَ بَاشِرُوهُنَّ وَابْتَغُوا مَا كَتَبَ اللَّهُ لَكُمْ وَكُلُوا وَاشْرَبُوا حَتَّىٰ يَتَبَيَّنَ لَكُمُ الْخَيْطُ الْأَبْيَضُ مِنَ الْخَيْطِ الْأَسْوَدِ مِنَ الْفَجْرِ ثُمَّ أَتِمُّوا الصِّيَامَ إِلَى اللَّيْلِ وَلَا تُبَاشِرُوهُنَّ وَأَنتُمْ عَاكِفُونَ فِي الْمَسَاجِدِ تِلْكَ حُدُودُ اللَّهِ فَلَا تَقْرَبُوهَا كَذَٰلِكَ يُبَيِّنُ اللَّهُ آيَاتِهِ لِلنَّاسِ لَعَلَّهُمْ يَتَّقُونَ ١٨٧

اللَّيْلِ al-layli · the night

It has been made permissible for you the night preceding fasting to go to your wives [for sexual relations]. They are a clothing for you and you are a clothing for them. Allāh knows that you used to deceive yourselves, so He accepted your repentance and forgave you. So now, have relations with them and seek that which Allāh has decreed for you [i.e., offspring]. And eat and drink until the white thread of dawn becomes distinct to you from the black thread [of night]. Then complete the fast until the night [i.e., sunset]. And do not have relations with them as long as you are staying for worship in the mosques. These are the limits [set by] Allāh, so do not approach them. Thus does Allāh make clear His verses [i.e., ordinances] to the people that they may become righteous. (Surah Al-Baqarah, 2:187)

وَإِذْ وَاعَدْنَا مُوسَىٰ أَرْبَعِينَ لَيْلَةً ثُمَّ اتَّخَذْتُمُ الْعِجْلَ مِن بَعْدِهِ وَأَنتُمْ ظَالِمُونَ ٥١

لَيْلَةً laylatan · nights

And [recall] when We made an appointment with Moses for forty nights. Then you took [for worship] the calf after him [i.e., his departure], while you were wrongdoers. (Surah Al-Baqarah, 2:51)