Overall meaning :
Allah Almighty directs His Prophet, may Allah bless him and grant him peace, to challenge the idolaters who ascribe partners to Him with this Qur’an, saying: Say to them, ‘If all humans and jinn were to gather together and agree to produce the like of this miraculous Qur’an, they could never produce its like, no matter how much assistance they lent one another.’
We have surely explained in diverse ways for mankind in this Qur’an all manner of arguments, proofs, exhortations, parables and lessons so that they may take heed, but most people stubbornly persist in rejecting the truth and refuse to accept anything other than unbelief.