Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(And if We cause man) the disbeliever (to taste some mercy) a blessing (from Us and afterward withdraw it from him, lo! he is despairing) he becomes the most despairing and despondent thing from Allah's mercy, (thankless) he denies Allah's blessing and is not grateful.
And if We cause, the disbelieving, man to taste some mercy from Us, [such as] wealth and [good] health, and then wrest it from him, lo! he is despairing, having lost hope of God’s mercy, ungrateful, intensely ungrateful to Him.
And if We cause man to taste some mercy from Us, to the end of this [verse]: man ought to have confidence in God, trusting in Him, in poverty, wealth, hardship, comfort, sickness and health and [should] not veil himself from Him by the existence of a grace or in his striving or conduct with regard to acquiring [his livelihood], or [veil himself] by his strength or power to pursue his needs or in any one of the ways or means whatsoever, lest there should be despair upon the loss of those means or [alternatively] ungratefulness, the wantonness of comfort or insolence when they are forthcoming such that he then becomes remote from God, exalted be He, and forgets Him so that God forget him. Rather, he should see the giving and the withholding as being from Him and no one else. And so if He should bring upon him a mercy in the way of health or a grace, he should thank Him first by seeing that as being from Him and witnessing the Gracious in the form of [His] grace, which is [done] with the heart then with the limbs by using them in that which satisfies Him and in acts of obedience to Him and by fulfilling His dues with regards to that [mercy]; then [he should thank Him] with his tongue by [words of] praise and laudation, fully certain that He has the power to strip [him] of it, and preserving it by giving thanks for it, seeking more of it on the basis of His saying, exalted be He: If you are thankful, then assuredly I shall give you more [Q. 14:7]. The Commander of the Believers [ʿAlī b. Abī Ṭālib], peace be upon him, said: 'If the edges of grace reach you, then do not repel the fullness of it by the sparsity of [your] thanks'. Then if He should wrest it from him, let him be patient and not grieve for it, in the full knowledge that it is He who has wrested it from him and no one else because of some welfare that will [ultimately] finds its way to him. For the Lord, exalted be He, is like a father who is compassionate in the nurturing of him, nay, He is more gentle and more merciful, since a father is veiled from what God knows seeing only the immediate and outward welfare, while He is the Knower of the unseen and the visible, knowing what is in his immediate and future best interest.
[Let him be] satisfied with His act and hopeful that what will be restored to him will be better than what was wrested from him. For the one who is utterly despondent [despairing] of His mercy is remote from Him, failing to perceive that His mercy is all-embracing because of the narrowness of his vessel [of preparedness], being veiled from [the reality of] His Lordship unable to see the generality and endurance of the effusion of His mercy. And so [the patient one] when He restores it to him, he is not exultant with its existence just as he did not grieve at losing it. And let him not boast of it to other people, for that is indeed ignorance and the manifestation of the soul. [Were he to see the effusion of His mercy] he would know that that [grace] is not from him or for him: so what reason does he have justify boasting of what is not for him or from him, but for God and from God;
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
This disgraceful characteristic of man has been mentioned here because the disbelievers were exhibiting it at that time. When the Holy Prophet warned them of the consequences of their disobedience to Allah, they would scoff at hire as if to say, "Arc you mad? Can't you see our prosperity and power? We are enjoying all the good things of life and dominating over everything and everyone all around us. How is it that you are prophesying torment for us?"
The above-mentioned arrogant behavior was due to the disgraceful human characteristic which has been mentioned in this verse. It is this: Man is, by nature, shallow and superficial and lacks the depth of thought. Therefore, when he enjoys prosperity and power he becomes joyous, arrogant and boastful; so much so that he never even dreams of any possibility that his happy condition would ever come to an end. And if and when adversity befalls him, he becomes an embodiment of despair and begins to complain of his misfortune here, there, and everywhere; so much so that he does not hesitate even to abuse God and taunt at His Godhead. But whenever there is a change for the better in his fortune, he again begins to brag of his foresight, wisdom and success. That is why the disbelievers were exhibiting such a shallow and superficial characteristic in answer to the warning of the Holy Prophet. They forgot that Allah was deferring their punishment because of His mercy to give them sufficient time to consider well their absurd attitude and mend their ways during the respite given to them, and not to delude themselves by imagining that their prosperity had very deep foundations and would last for ever.
Here (sabr) (fortitude) implies another meaning also, that is, "steadfastness" the antonym of shallowness etc., that has been mentioned in the preceding verse. Those "who are steadfast" remain fine and unwavering in their purpose in spite of the vicissitudes of life. They are not influenced by the changes of circumstances, but stick to the right, reasonable and correct attitudes they have adopted. They do rot give themselves airs nor become intoxicated nor over-jubilant and boastful, if they win power, prosperity and name. On the contrary, they are neither subdued nor depressed if they are visited by adversity. In short, they come out successful in their trial by Allah, whether it be in the shape of favor or adversity and remain steadfast in both the cases.
This is the favor that Allah shows to such people; He forgives their shortcomings and gives them rich rewards for their good deeds.