Surah Adh-Dhariyat 51:18

وَبِٱلْأَسْحَارِ هُمْ يَسْتَغْفِرُونَ

And in the hours before dawn they would ask forgiveness,

Translation: Saheeh International

Tafsir

and at dawns they used to seek forgiveness they used say ‘Our Lord! Forgive us’

Excerpt from Tafsir al-Jalalayn, commentary on 51:18, via Quran.com. The reader has the full commentary and 9 more tafsirs.