Surah Ad-Duhaa 93:2
وَٱلَّيْلِ إِذَا سَجَىٰ
And [by] the night when it covers with darkness,
Translation: Saheeh International
Tafsir
and by the night when it is still — or sajā can mean ‘when it envelops all in its darkness’.
Excerpt from Tafsir al-Jalalayn, commentary on 93:2, via Quran.com. The reader has the full commentary and 9 more tafsirs.