(Swaffaath) 37 : 1
بِسْمِ اللَّهِ الرَّحْمَٰنِ الرَّحِيمِ وَالصَّافَّاتِ صَفًّا

By those who lined up in ranks.

This verse mentions about the angels. In verse 165 it is told that we are lined up in ranks. That means the angels are always vigilant to obey the command of Allah. It is told in verse 66: 6 that the angels do not disobey Allah in what He commands them, and they are doing whatever they are commanded with. The birds which can pause still in the air spreading their wings are called “Swaffaath-Spreading the Wings”. As told in verse 35: 1 since angels are created with wings like the birds, angels are mentioned in feminine gender. And that is not because the angels are females, but it is because birds are mentioned in feminine gender in Arabic language. See explanation 19: 64; 53: 26-27; 67: 19.