Is he whose breast is opened to Islam , and who is therefore illuminated by his Lord…? Woe to those whose hearts are hardened against the remembrance of Allah! Such people are clearly misguided. ( Surat az-Zumar, 39:22)
The existence of Allah and the Hereafter is obvious. Despite this, however, the majority of people have no faith. A person attains true faith only when Allah “opens one's breast to Islam.” This acquisition of faith is the greatest blessing from Allah, for if Allah had no mercy and favor upon His sincere servants, none of them would attain salvation. While creating humanity, Allah gave every soul a lower self that would tempt each man and woman toward evil. However, He also ensured that His sincere servants could attain the straight path by both overcoming and avoiding such temptations.
This right path, which is attained by following one's conscience, is a blessing granted to sincere believers. As Allah informs us:
... However, Allah has given you love of faith and made it pleasing to your hearts, and has made disbelief, deviance, and disobedience hateful to you. People such as these are rightly guided. It is a great favor from Allah and a blessing. ( Surat al-Hujurat, 49:7-8)
Those who forget how they were created and insist on unbelief, despite all of the signs surrounding them, who follow the dictates of their lower selves and do not exercise their conscience, will experience the following:
As for those who are unbelievers, it makes no difference to them whether you warn them or do not warn them; they will not believe. Allah has sealed up their hearts and hearing, and over their eyes is a blindfold. They will have a terrible punishment. ( Surat al-Baqara, 2:6-7)
Have you seen him who takes his whims and desires to be his deity—whom Allah has misguided knowingly, sealing up his hearing and his heart and placing a blindfold over his eyes? Who, then, will guide him after Allah? So will you not pay heed? ( Surat al-Jathiya, 45:23)