And let not those who disbelieve ever think that [because] We extend their time [of enjoyment] it is better for them. We only extend it for them so that they may increase in sin, and for them is a humiliating punishment.
(And let not those grieve you who rush with haste to disbelieve) 3:176.
Because the Prophet was eager for people's benefit, he would become sad when the disbelievers would resort to defiance, rebellion and stubbornness. Allah said, `Do not be saddened by this behavior,'
(verily, not the least harm will they do to Allah. It is Allah's will to give them no portion in the Hereafter.) for He decided with His power and wisdom that they shall not acquire any share in the Hereafter,
Material affluence of disbelievers is, after all, an extension of Divine punishment
Let there be no doubt about the worldly wellbeing of disbelievers for one may be tempted to believe that since Allah Almighty has given respite, long life, security and comfort to disbelievers so that they go on increasing in their crimes, they should, then, be taken as innocent. Far from it, because the verse means that Muslims should not feel upset about this temporary respite and affluence given to disbelievers as all this worldly wealth and power in their hands - despite their disbelief and disobedience - is nothing but a form of the very punishment destined for them. Today, they do not realize it. But, once they leave the mortal world, they would. They would discover to their dismay that all those articles of comfort they acquired and spent in sin were, in reality, the very embers of Hell. This is corroborated by several other verses of the Qur'an. For instance, (Allah intends to punish them with it – 9:55) which means that the wealth and power of disbelievers and their vulgarly luxurious consumerism should not be a matter of pride for them for this is nothing but an installment of that very punishment from Allah which will cause their punishment in the Hereafter to increase.
Tazkirul Quran
Maulana Wahiduddin Khan
The real problem is that, being veiled from our eyes, life is not what it appears to be. People are concerned with saving themselves from ‘hell’ (the difficulties and problems of this world) and devote all their attention to attaining the ‘paradise’ of this world. But it would be wiser to aim for the Paradise of the next world and in so doing save oneself from the Hell of the next world. Wealth, property and the trappings of honour are things that everyone can see with his own eyes. That is why man relentlessly pursues these goals, exerting himself to the utmost, so as not to be deprived of them. But the actual human dilemma is the question of the Hereafter. This real problem has been screened from our eyes, because human beings have to be put to the test by God. However, God has His way of informing people of it. This is done by selecting His messengers from amongst men, so that they may make people aware of the realities beyond death. The real test of man is to discover the truth in the message of the preacher (da‘i) appointed by God. He may see the actual reality in a verbal message. He may hear the divine voice in the voice of a human being. God speaks through His messengers—human beings. Now man has to acknowledge a man like himself as one receiving the divine message.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.