question #1 Sahih Muslim 118, Book 1, Hadith 220 : Why is it important to be prompt in doing good deeds according to Islamic teachings?

Be prompt in doing good deeds (before you are overtaken) by turbulence which would be like a part of the dark night. During (that stormy period) a man would be a Muslim in the morning and an unbeliever in the evening or he would be a believer in the evening and an unbeliever in the morning, and would sell his faith for worldly goods.