The disappearance of the light of fitrah:

 The fitrah is a genuine feeling in the human soul. This applies to the learned and the ignorant, the townsman and the villager, men and women, and previous and later generations. The evidence for this is taken from the reality of man and his experiences. Man often invokes his Lord, Who responds to his invocation; he calls Him and He hearkens to him; he asks Him and He gives him; he relies on Him and He satisfies him.[1]

 When man lives in prosperity and security after living in straitened circumstances and insecurity, he may forget his Lord and Cherisher and get occupied with his worldly affairs, forgetting the One Who has bestowed His favor on him and freed him from his suffering. Allah (SWT) says: “When some trouble touches man, he cries unto his Lord, turning to Him in repentance: but when He bestows a favor upon him as from Himself, (man) does forget what he has cried and prayed for before, and he does set up rivals unto Allah, thus misleading others from Allah’s Path.” (XXXIX: 8) In the interpretation of the verse we read: “The fitrah of the human appears undisguised when evil afflicts him. The burdens drop away from it, curtains are removed from it and it is disillusioned, whereupon it turns to its Lord only in repentance, being aware that none other than He can remove the mischief. It knows the falsity of the alleged notion of partners and intercessors. But when the mischief is removed and prosperity replaces it, and when Allah bestows a grace upon him and removes his affliction from him, the man whose fitrah was uncovered when he was in affliction starts piling on it the burdens of ingratitude and forgets his previous supplication, repentance, the observation of the Oneness of his Lord and his appealing to Him alone, for none other than He could rescue him from his dilemma… He forgets all this and sets up rivals to Him.”[2] Allah sets up a detailed example for this to make it clearer in the minds. Allah (SWT) says: “He is the One who enables you to traverse land and sea. But when you get onto the ships, and they sail smoothly in a nice breeze and then they are pleased therewith, a violent wind overtakes them and the billows surge in on them from all sides and they think they are being overwhelmed, they implore Allah sincerely devoting their prayers to Him alone: ‘If You only save us this time, we truly will be of the thankful.’ But when he delivered them, behold! They transgress insolently through the earth in defiance of right!” (X: 22-23)

 Allah (SWT) lets those who deviate from the religion go astray and He never guides them. Allah (SWT) says: “When they deviated, Allah diverted their hearts, for Allah does not guide the wicked people.” (LXI: 5)