Warnings to those who reject Faith

Those who reject Faith will not believe and will face punishment
6. As to those who reject Faith, it is the same to them whether thou warn them or do not warn them; they will not believe.

7. God hath set a seal on their hearts and on their hearing, and on their eyes is a veil; great is the penalty they (incur).

(Surah 2, The Cow)

Those who falsely believe will face a punishment for being false to themselves
8. Of the people there are some who say: "We believe in God and the Last Day;" but they do not (really) believe.

...

10. In their hearts is a disease; and Allah has increased their disease: And grievous is the penalty they (incur), because they are false (to themselves).

(Surah 2, The Cow)

False believers will be mocked, punished, and be made to wander, not returning to the path
8. Of the people there are some who say: "We believe in God and the Last Day;" but they do not (really) believe.

...

15. God will throw back their mockery on them, and give them rope in their trespasses; so they will wander like blind ones (To and fro).

16. These are they who have bartered Guidance for error: But their traffic is profitless, and they have lost true direction,

(Surah 2, The Cow)

Unbelievers will be left in darkness and in fear, even with temporary light (and cannot escape God)
17. Their similitude is that of a man who kindled a fire; when it lighted all around him, God took away their light and left them in utter darkness. So they could not see.

18. Deaf, dumb, and blind, they will not return (to the path).

19. Or (another similitude) is that of a rain-laden cloud from the sky: In it are zones of darkness, and thunder and lightning: They press their fingers in their ears to keep out the stunning thunder-clap, the while they are in terror of death. But God is ever round the rejecters of Faith!

20. The lightning all but snatches away their sight; every time the light (Helps) them, they walk therein, and when the darkness grows on them, they stand still. And if God willed, He could take away their faculty of hearing and seeing; for God hath power over all things.

(Surah 2, The Cow)