15. Some commentators have given this meaning of this verse: Seldom did it so happen that they spent the whole night sleeping and did not spend a part of it, in the beginning of the night or in the middle or in the end of it, awake in the worship of Allah. This commentary with a little variation in wording has been related from lbn Abbas, Anas bin Malik, Muhammad al-Baqir, Mutrif bin Abdullah, Abul Aliyah, Mujahid, Qatadah, Rabi bin Anas and others. According to some other commentators, it means this: They spent the major part of their nights in the worship of Allah Almighty and slept little. This meaning has been reported from Hasan Basri, Ahnaf bin Qais, and Ibn Shihab Zuhri, and the later commentators and translators have preferred this, for this appears to be in better agreement with the words of the verse and the context.
16. That is they did not belong to those who spent their nights in immoral and indecent acts and even then never thought of seeking Allah’s forgiveness. On the contrary, they spent a major part of the nights in the worship of Allah and then in the early hours of dawn sought His forgiveness, saying that they did not do full justice to the worship that was due from them. The words humyastaghfirun also contain an allusion to this that it befitted and suited them alone that they should exert their utmost in the service of their Lord and then, at the same time, should implore Him humbly for the forgiveness of their errors and shortcomings instead of exulting at and waging proud of their good acts. This could not be the way of those shameless, wicked people who committed sin and behaved arrogantly as well.