Allah is informing us that He never destroys a township until He has established evidences for it and its allotted time has ended. When the time for a nation's destruction has come, He never delays it, and He never moves its appointed time forward. This was a message and a warning to the people of Makkah, telling them to give up their Shirk, their stubbornness and disbelief for which they deserved to be destroyed.
Ma'arif al-Qur'an
Mufti Muhammad ShafiOn ayahs 3–7
Commentary
From: ذَرْهُمْ يَأْكُلُوا (Let them eat ...3) we can see that the making of eating and drinking the real occupation and aim of life, and keeping glued to long-drawn material plans while surrounded by countless things of worldly comfort, and becoming totally heedless to death, is something which can be done only by the disbelievers. The reason is that they do not believe in the 'Akhirah, the life to come, and the accounting of deeds there, and the reward and punishment for it. As for eating and drinking, a believer does it too, and takes care of economic needs to the measure of necessity, and makes future plans for occupation and business as well. But, a believer would not make all these efforts by forget-ting death and ignoring the concern for 'Akhirah. Therefore, he is careful about everything he does and finds out whether it is Halal or Haram, permissible or forbidden. Then, he does not occupy himself in the making of wasteful or unnecessary plans and projections, as hobby or compulsion. The Holy Prophet ﷺ said: Four things are signs of being unfortunate: (1) Not being able to shed tears (that is, not being in tears when ashamed of acts of negligence and sin); (2) and hard-heartedness; (3) fanciful hopes and plans for the future; (4) and the greed for worldly things. (Qurtubi from Musnad al-Bazzar from Sayyidna Anas ؓ
The freedom enjoyed by man will last only for the duration of the period of testing. This is a very critical issue. If a man seriously thinks this problem over, he will feel that the period which is going to end tomorrow has, as it were, ended today itself. This thought will shake him terribly. But man lives his life in ‘today’. He does not pay attention to ‘tomorrow’. Reality lies exposed before him, but he remains engrossed in wishful thinking. He seeks out some imaginary supports of his own devising and thinks that they will help him on the Day of Judgement. But such wishful thinking will not come to his rescue when the period of testing is over and God’s angels come to take him away from the world of trial to the world of retribution. At a time like this, he starts remembering the occasions when he had tried to reject a genuine argument by mouthing false words; when he had ignored the voice of his conscience and followed the desires of the self; when purely out of self-interest he had ignored the divine preacher of truth, in spite of seeing glimpses of God in him. When he sees that no device of his has been of any avail, he will say, ‘Alas! I should not have done what I have done! I should have adopted the way of one who surrenders to the Truth instead of the way of one who rejects the Truth.’
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.