Al-Bukhari recorded that `Abdur-Rahman bin Yazid said that `Abdullah said, "Banu Isra'il, Al-Kahf, Maryam, Ta Ha and Al-Anbiya' - they are among the earliest and most beautiful Surahs and they are my treasure."
بِسْمِ اللَّهِ الرَّحْمَـنِ الرَّحِيمِ
In the Name of Allah, the Most Gracious, the Most Merciful.
The Hour is at hand but People are heedless
This is a warning from Allah of the approach of the Hour, and that people are heedless of it, i.e., they are not working for it or preparing for it. An-Nasa'i recorded that Abu Sa`id reported from the Prophet :
أَفَتَأْتُونَ السِّحْرَ وَأَنتُمْ تُبْصِرُونَ (Would you then go along with sorcery while you have eyes to see? - 21:3) Those people used to discuss among themselves secretly that the claim of the Holy Prophet about his prophethood should not be accepted, because he was an ordinary human being like all others and not an angel. On the other hand not even the most rigid among the unbelievers could deny the supreme charm and eloquence of the Book of Allah nor its power to influence people when it was recited before them. Therefore, in order to turn people away from the Holy Book they started calling it magic and black art. They thought that they could keep people away from Islam by labeling the Qur'an as a book of magic thereby dissuading people from going to the Holy Prophet ﷺ and listening to Qur'an. Probably they used to discuss this subject secretly among themselves lest the Muslims come to know about their foolish views and unveil their fallacy.
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 4–5
Every man who is living in this world is nearer to death than life. In this respect he is virtually on the verge of coming face to face with his Day of Reckoning. But man is so reckless that he does not pay heed to any sort of reminder from God, whether given through a prophet or anyone else. He ignores the advice of the preacher of truth and dismisses it as something uttered by ‘a mere man’. When in Makkah the Prophet Muhammad started calling upon people to God by means of the Quran. The divine discourse enshrined therein moved people’s hearts. This became a serious matter for the Makkan leaders, because this jeopardized their leadership. The Quran urged people to accept the unity of God, whereas the great leaders of Makkah had maintained their supremacy on the basis of polytheism. In order to divert the attention of the people, they started spreading the notion that the effectiveness of the Prophet Muhammad’s message did not derive from its being the word of God; the force behind it was not that of Truth but of magic. It was all mere human rhetoric and was in no way to be considred a divine discourse. Albeit taking the name of God, those who indulged in such talk did not firmly believe that God was seeing and hearing them. Had they had real faith in God’s being all-knowing, that is, His being One who knows the unseen—they would never have uttered such insincere words.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.