I’jaaz (inimitability of) Al-Qur’aan:
Allah Ta’Aalaa sent Muhammad (saw) amongst a people who were eloquent and pure of tongue (i.e. in language). They had seasonal markets and fairs in which they would compete in respect to the purity, beauty and eloquence of their poetry. The winning poetry would then be written in gold and hung upon the walls of the Ka’bah which was their most sanctified and sacred place. The news would then spread and the tribes would gain pride and honour through this. Within this reality Allah Ta’Aalaa provided Muhammad (saw) with a miracle which was of the same kind or within the same category that they found pride and honour in. It was Arabic speech utilising the same letters and expressions that they would formulate their poetry from and it was the Kalaam (speech) of Allah that was miraculous and inimitable (impossible for humans to replicate).
Allah challenged the Arabs with the Qur’aan by challenging them to bring something similar and like it and indeed even to just bring one Soorah that was similar to it. Allah Ta’Aalaa said:
Or do they say [about the Prophet]: “He invented it?” Say: "Then bring forth a Surah like it and call upon [for assistance] whomever you can besides Allah, if you should be truthful” (Younus 38).
And He Ta’Aalaa said:
Say: "If mankind and the jinn gathered in order to produce the like of this Qur'an, they could not produce the like of it, even if they were assistants to one another" (Al-Israa’ 88).