Ан-Наба 78:9

وَجَعَلْنَا نَوْمَكُمْ سُبَاتًا (and made your sleep a source of rest,...78:9). The word subat is derived from sabt which means to cut off. Sleep is something that cuts off the worries and tensions one may have, and thus gives him such a rest that cannot be attained from anything else. Therefore, some scholars translate the word subat as 'rest'.

Sleep Is a Great Gift

After mentioning in verse [ 8] that Allah has created mankind in pairs, Allah Ta’ ala states in verse [ 9] that among the means of their comfort, He created sleep, which is a great divine gift. Sleep is a great source of relaxation for the entire creation - for rich as well as for poor, for learned people, as well as for the illiterate ones, for kings as well as for labourers. This gift is made available equally and simultaneously for all. Rather, experience shows that this gift is most readily available to the poor and labouring class, as compared to the affluent and the elite class. The latter class has all the means of comfort, they have comfortable homes, they have moderately warm and cold places, they have comfortable mattresses and pillows that are rarely available to the poor. But the gift of sleep is not dependent upon the mattresses, pillows, cottages and bungalows. It is purely a divine gift that is given directly by Allah. Often the poor, with no means of comfort and without bed or bedding, enjoy the best sleep in an open space. Sometimes, the affluent and the men of means suffer from insomnia and can only get sleep when they take sleeping pills. Often the pills do not work either. Not only that this great gift is given to all creatures - humans as well as animals - and it is given free of charge, without working for it. Allah has made it compulsory for everyone in a way that even if he wishes to keep awake because of load of work, sleep is imposed on him by Allah's mercy, so that his tiredness is removed and he is refreshed to work further. This arrangement is a wonderful means of providing rest and peace for man.