Translation:

18. And in the hours of early dawn They (were found) praying for Forgiveness;

Notes (Tafseer)

5000. They were up early before dawn, ready for their devotions. The praying for Forgiveness and Mercy does not necessarily imply that they had committed fresh sins. Indeed they began the day with such devotions, showing their great humility before Allah and their anxious care for others, for whom they prayed as much as for themselves. See the last sentence of n. 21 to i. 5.