Why did Allah challenge humanity to produce a single verse like that of the Quran, and they were unable to do so? And what is the miraculous aspect of its verses?

Allah Almighty challenged humankind and jinn to produce a likeness of the Qur’an or even a single surah from it, to prove that it is the word of Allah, revealed to the heart of His Prophet Muhammad (peace be upon him), and not composed by humans. The Qur’an is miraculous in its words, structure, style, meanings, legislation, stories, prophecies of the unseen, and its influence on souls. People continue to discover aspects of its miraculousness, fulfilling Allah's saying: ﴿We will show them Our signs in the horizons and within themselves until it becomes clear to them that it is the truth.﴾