Allah takes the souls {1} (i.e. consciousness of human beings) at the time of their death, and (He takes the soul) of the person who does not die, during his sleep, then He withholds that on which He has decreed death and sends (back) the others till an appointed term. Certainly there are signs in that for a people who reflect.
Refer to Note No.1 (39:42) of Explanatory Notes and Commentary; Chapter:4 Verse 1 on Nafs page No.151
The ‘nafs’ is something that is taken away from us by Allah at the time of death and during sleep, when we are biologically alive but unconscious. ‘Nafs’ translated as ‘soul’, mind,’ or ‘self’ is therefore our state of consciousness which is present in us when we are awake and which is responsible for our deliberate actions. It is the unseen inner self which we can recognize when we say ‘I’, ‘me’, ‘my’ etc.