Abu Hurayrah (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "Hasten to good deeds before being overtaken by tribulations that are like parts of the dark night. A man would be a believer in the morning and turn to a disbeliever in the evening, or he would be a believer in the evening and turn to a disbeliever in the morning. He sells his religion for a worldly gain.”
شرح الحديث :
This Hadīth prompts doing good deeds before one is prevented from doing so. There will be tribulations as dark as night, through which one will not see the light of truth. As such, one will turn into a disbeliever and vice versa with the alternation of day and night, selling his religion for a worldly gain, be it wealth, status, authority, women, or something else.