When the Quraish was bewildered by the style of Qur’an, they came to Walid bin Mughira who was among the intellectuals of Arabs and was famed for his literary expertise and philosophy, and told him to come and listen to the discourses of the Holy Prophet (S) and tell them what it actually was.
He came to the Holy Prophet (S) and said: “O Muhammad, recite your poems.” The Messenger of Allah (S) said: “They are not poems, it is the discourse of the Almighty Allah sent for the prophets,” and he recited the verses of Surah Ha Mim. When he reached the following verse:
فَإِنْ أَعْرَضُوا فَقُلْ أَنْذَرْتُكُمْ صَاعِقَةً مِثْلَ صَاعِقَةِ عَادٍ وَثَمُودَ.
“But if they turn aside, then say: I have warned you of a scourge like the scourge of Ad and Thamud.”88
…he began to tremble and his hair stood on their ends. After that he arose silently and went home. Quraish was worried lest he embrace Islam. He was an uncle of Abu Jahl. Abu Jahl came to him and said: “Uncle, by inclining to the religion of Muhammad you have insulted us.” He said: “No, I am on your religion, but I heard such a meaningful discourse from Muhammad that makes one tremble.” Abu Jahl asked: “Is it poetry,” to which he replied in the negative. “Is it a sermon?” “No, a continuous speech is called a sermon whereas it was disjoined discourse, but contains such beauty and sweetness that cannot be fully described.”
He said, “It must be soothsaying.” “No.” Abu Jahl asked, “Then what should we refer to as?” “Wait for a couple of days and allow me to think upon it.” Later he said, “It is a magical discourse as it bewitches the people.”
Reference:Hayat Al-Qulub Vol. 2