The Quran

أَوَلَم يَرَوا أَنّا جَعَلنا حَرَمًا آمِنًا وَيُتَخَطَّفُ النّاسُ مِن حَولِهِم ۚ أَفَبِالباطِلِ يُؤمِنونَ وَبِنِعمَةِ اللَّهِ يَكفُرونَ

Muhammad Asad

Are they, then, not aware that We have set up a sanctuary secure [for those who believe in Us], the while all around them men are being carried away [by fear and despair]?¹ Will they, then, [continue to] believe in things false and vain, and thus God's blessings deny?

See note 58 on the second paragraph of 28:57. In contrast to the "sanctuary secure" - the inner peace and sense of spiritual fulfilment which God bestows on those who truly believe in Him - the atheist or agnostic is more often than not exposed to fear of the Unknown and a despair born of the uncertainty as to what will happen to him after death.