Disbelievers will not believe whatever they are told about God the One the Almighty and about the Hereafter and the Judgment and Requital or Reward ... because God does not guide them .. and for this reason, He set a veil on their sight lest they should believe and impairment on their hearing and covering on their hearts lest they might hear or understand... so they left for devils to lead them astray and immerse them more in sins and disobedience .. therefore, they keep mocking God and His messenger and His Quran.
Quran 2: 6-7 which mean:
6. Surely, those who deny [you, Mohammed, and the Quran]; it is the same to them – whether you warn them or you warn them not – they will not believe.
a
7. God has set a seal [of "Rayn" which is the rust] upon their hearts and [deafness] on their hearing, and on their sights is a veil [lest they should convert]
b, and there awaits them a grievous chastisement.
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6 a Because they are wrong-doers: they wrong people; and God does not guide the wrong-doer, but misguides him.
The indication of this is His saying – be glorified – in the Quran 14: 27 which means: (God misguides the wrong-doer, and God does what He pleases.)
7 b because they are wrong-doers, and God does not guide the wrong-doer.
quran-ayat.com/pret/2.htm#a2_6