Translation of the verse 5 from Surah Al-Fajr : Number of verses 30 - - page 593 - Part 30.
There is indeed in them (the above oaths) sufficient proofs for men of understanding (and that, they should avoid all kinds of sins and disbeliefs, etc.)!
Is there [not] in [all] that an oath [sufficient] for one of perception?
(89:5) Is there in this an oath for one endowed with understanding? *1
*1) Much difference of opinion has been expressed by the commentators in the commentary of these verses, so much so that in respect of "the even and the odd" there are as many as 36 different views. In some traditions the commentary of these verses has also been attributed to the Holy Prophet lupon whom be peace), but the fact is that no commentary is confirmed from him, otherwise it was not possible that anyone from among the Companions, their immediate successors, and later conunentators would have dared to determine the meaning of these verses by himself after the conmentary by the Holy Prophet.
After a study of the style one clearly feels that there was an argument alredly in progress in which the Holy Prophet (upon whom be peace) was presenting some thing and the disbelievers were denying it. At this, affirming what the Holy Prophet presented, it was said: By such and such a thing", so as to say: "By these things, what Muhanunad (upon whom be Allah's peace and blessings) says is wholly based on the truth ' Then, the argument is concluded with the question: "Is there an oath in it for a man of understanding ?" That is, "is there need for yet another oath to testify to the truth of this matter ''" Is this oath not enough to persuade a sensible man to accept that which Muhanunad (upon whom be Allah's peace and blessings) is presenting '?"
Now the question arises: what was the argument for the sake of which an oath was sworn by these four things '? For this we shall have to consider the whole theme which, in the following verses, commences with: "Have you not seen how your Lord dealt with the 'Ad" and continues till the end of the Surah. It shows that the argument concerned the rewards and punishments of the Hereafter, which the people of Makkah were refusing to acknowledge and the Holy Messenger (upon whom be peace) was trying to convince them of this by constant preaching and instruction. At this oaths were sworn by the dawn, the ten nights, the even and the odd, and the departing night to assert: Are these four things not enough to convince a sensible man of the truth of this matter so that he may need yet another evidence for it?
After having determined the significance of these oaths in the context, we would inevitably have to take each of these in the meaning relevant to the subsequent theme. First of all, it is said: "By Fajr." Fajr is the breaking of day, i.e. the time when the first rays of the light of day appear in the midst of the darkness of night as a white streak from the east. Then, it is said: "By the ten nights." If the context is kept in view, it will become plain that it implies each group of the ten nights among the thirty nights of the month, the first ten nights being those during which the crescent moon starting as a thin nail. goes on waxing every night until its major portion becomes bright; the second group of the ten nights being those during which the greater part of the night remains illumined by the moon, and the last ten nights being those during which the moon goes on waning and the nights becoming more and more dark until by the end of the month the whole night becomes absolutely dark. Then, it is said : "By the even and the odd." Even is the number which is divisible into two equal parts, as 2, 4, 6, 8, and the odd the number which is not so divisible, as l, 3, 5, 7. Generally, it may imply everything in the universe, for things in the universe either exist in pairs or as singles. But since the context here concerns the day and the night, the even and the odd mean the alternation of day and night in the sense that the dates of the month go on changing from the first to the second, and from second to the third, and every change brings with it a new state. Last of all, it is said: "By the night when it is departing", i.e. when the darkness which had covered the world since sunset may be at the verge of disappearing and the day be dawning.
Now let us consider as a whole the four things an oath by which has been sworn to assert that the news which Muhammad (upon whom be Allah's peace and blessings) is giving of the meting out of rewards and punishments is wholly based on the truth. All these things point to the reality that an all-Powerful Sustainer is ruling over this universe, and nothing of what He is doing is absurd, purposeless, or lacking wisdom; on the contrary, a wise plan clearly underlies whatever He does. In His world one will never see that while it is night, the midday sun should suddenly appear overhead, or that the moon should appear one evening in the shape of the crescent and be followed next evening by the full moon, or that the night, when it falls, should never come to an end, but should become perpetual, or that there should be no system in the alternation of the day and night so that one could keep a record of the dates and know what month was passing, what was the date, on what date a particular work is to begin, and when it is to finish, what are the dates of the summer season and what of the rainy or winter season. Apart from countless other things of the universe if man only considers this regularity of the day and night intelligently and seriously, he will find evidence of the truth that this relentless discipline and order has been established by an Omnipotent Sovereign God; with it are connected countless of the advantages of the creatures whom He has created on the earth. Now, if a person living in the world of such a Wise, Omnipotent and All-Mighty Creator denies the rewards and punishments of the Hereafter, he inevitably commits one of the two errors: either he is a denier of His powers and thinks that though He has the power to create the universe with such matchless order and discipline, He is powerless to recreate man and mete out rewards and punishments to him or he denies His wisdom and knowledge and thinks that although He has created man with intellect and powers in the world, vet He will neither ever call him to account as to how he used his intellect and his powers, nor will reward him for his good deeds, nor punish him for his evil deeds. The one who believes in either, is foolish in the extreme.
Source : Al-Fajr Verse 5: Is there [not] in [all] that an oath [sufficient] for one of perception?