وَمِنَ اللَّيْلِ فَسَبِّحْهُ
And in the nighttime also glorify His praises,
meaning remember and worship Allah by reciting the Qur'an and praying at night. Allah the Exalted said in another Ayah,
وَمِنَ الَّيْلِ فَتَهَجَّدْ بِهِ نَافِلَةً لَّكَ عَسَى أَن يَبْعَثَكَ رَبُّكَ مَقَاماً مَّحْمُودًا
And in some of the night, offer Tahajjud in it as an additional (prayer) for you. It may be that your Lord will raise you to Maqam Mahmud. (17;79)
and at the setting of the stars.
is in reference to the two voluntary Rak`ahs before the Dawn prayer, according to a Hadith from Ibn Abbas. These two Rak`ahs are an established Sunnah performed before the stars are about to set.
It is confirmed in the Two Sahihs from A'ishah, may Allah be pleased with her, who said,
"The Prophet was never more regular and particular in offering any voluntary prayer than the two (Sunnah) Rak`ahs of the Fajr prayer."
In another narration collected by Muslim, the Prophet said,
رَكْعَتَا الْفَجْرِ خَيْرٌ مِنَ الدُّنْيَا وَمَا فِيهَا
Two (Sunnah) Rak`ahs before Fajr are better than this life and all that in it.
This is the end of the Tafsir of Surah At-Tur, all praise and gratitude is due to Allah