2. And by the day when it brightens(1)
1. Here, the oath is either on day and night in general because night is the reminder of death and day is the reminder of the Day of Judgement. Furthermore, the nights conceal man's knowledge, senses, strengths and power from which one learns that these are not our own things. Also, that reveals who is a transgressor, a pious person, a negligent person and who engrosses himself in the remembrance of Allah Almighty. It is during the night that burglars, adulterers and immoral roguish persons engage themselves in these criminal activities, while the true devotees engage themselves in Tahajjud Prayer, weeping to their Lord.
Since the night precedes the day and is superior to it, it is mentioned before the day followed by that of the day. Or, by night and day is meant those days and nights of Hazrat Bilal, which he spent at the home of Umayyah bin Khalf in sincere remembrance of Allah under those severe adverse conditions. Since everything of the beloved is dear, therefore oath is taken on those nights and days of Hazrat Bilal. Or, by night and day is meant the nights and days of the true devotees, because their nights are spent in the thinking of their True Friend and the days are spent in the remembrance of the Friend. Therefore, oath is taken on them. Or, by night is meant the moments of negligence of the believer in which he commits errors, while by day is meant the moments of wakefulness in which he repents and weeps to his Lord. Since the sin of the believer is his means of shedding tears, seeking repentance and expressing remorse, therefore oath is taken on them as well. The sin which brings about repentance is superior to worship which leads to pride. The eating of wheat by Hazrat Adam (On whom be peace) is superior to the entire worship of Shaitan.
