Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(Of His mercy) of His blessing (hath He appointed) He created (for you night and day that therein ye may rest) that you may rest at night, (and that ye may seek His bounty) that during the day you may seek His bounty through knowledge and worship, (and that haply ye may be thankful) so that you give thanks for the blessing of the day and the night that He has given you.
And of His mercy, exalted be He, He has made for you night and day, that you may rest therein, in the night, and that you may seek, in the day, of His bounty, to earn [your livelihood], that perhaps you might give thanks’, for the grace [of God] during both of these [times].
Night and Day are among the Blessings of Allah and are Signs of Tawhid
Allah reminds His servants of His favors towards them by subjugating for them the night and day, without which they could not survive. He explains that if He made the night continuous, lasting until the Day of Resurrection, that would be harmful for them and would cause boredom and stress. So He says:
مَنْ إِلَـهٌ غَيْرُ اللَّهِ يَأْتِيكُمْ بِضِيَآءٍ
(which god besides Allah could bring you light) meaning, `with which you could see things and which would bring you relief'
(Will you not then hear) Then Allah tells us that if He had made the day continuous, lasting until the Day of Resurrection, that would also be harmful for them and their bodies would get tired from so much movement and activity. Allah says:
(which god besides Allah could bring you night wherein you rest) meaning, `to rest from your work and activity.'
أَفلاَ تُبْصِرُونَوَمِن رَّحْمَتِهِ
(Will you not then see It is out of His mercy) towards you,
جَعَلَ لَكُمُ الَّيْلَ وَالنَّهَارَ
(that He has made for you the night and the day) He created both,
(that you may rest therein) during the night,
وَلِتَبْتَغُواْ مِن فَضْلِهِ
(and that you may seek of His bounty) during the day, by traveling, moving about and working.
(and in order that you may be grateful.) So that you may give thanks to Allah by performing all kinds of acts of worship at night and during the day. Whoever misses something during the night can make it up during the day, and vice versa. This is like the Ayah,
(And He it is Who has put the night and the day in succession, for such who desires to remember or desires to show his gratitude.) (25:62). And there are many similar Ayat.
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
This, in fact, is a refutation of shirk. Allah objects to the setting up of countless gods froth among His creatures by the mushriks and assigning to them from themselves of attributes and ranks and offices, and says: "We Ourselves bless with whatever attributes, capabilities and powers whomever We like from among the men, angels, jinns and other servants whom We have created, and employ whomever We will for whatever service We will. But, how and where from have the mushriks got the authority that they should make whomever they like from among My servants remover of hardships, bestower of treasures and answerer of prayers? That they should make someone the lord of rain, another the giver of jobs and children, still another bestower of health and ill-health? That they should look upon whomever they please as the ruler of a part of My Kingdom and assign to him whichever of My powers they like? Whether it is an angel or a jinn, or a prophet, or saint, or anybody else, he has been created by Us Whatever excellences he has, have been granted by Us, and whatever service We willed to take from him, We have taken. Therefore, the selection. of someone for a particular service does not mean that he should be raised from the position of a servant to godhead and worshiped instead of God, invoked for help, prayed to for fulfillment of needs, taken as maker or destroyer of destinies and possessor of divine; attributes and powers.
The object for which this thing has been said in this context is: A person (or persons) can make a claim before the people in this world that he is fully satisfied on rational grounds that the deviation he has adopted is sound and right, and the arguments that are given against it are not convincing; that he has adopted the deviation not due to any evil motive but with the sincerest and purest intentions; that he has never been confronted by anything that might have proved him to be in the wrong. But he cannot advance such an argument before Allah, for Allah is not only aware of the open, but also of the hidden secrets of the mind and heart: He knows directly what kind of knowledge and feelings and sentiments and desires and intentions and conscience a certain person has: He is aware of the occasions and the means and the ways through which a person was warned, through which the Truth reached him, through which falsehood was proved to be Falsehood to him, and also the real motives for which he preferred his deviation to the Right Way.