Perform Ghusul carefully and thoroughly .

This hadith is about the importance of performing ghusl for janabah properly and thoroughly. It was narrated by 'Ali ibn Abi Talib that he heard the Messenger of Allah say that if someone does not perform ghusl properly and leaves a space as small as a hair without pouring water on it, then such and such will be done to them in the Fire. From this hadith we learn that it is important to take care when performing ghusl for janabah so as to ensure that all parts are washed with water. We also learn from this hadith how serious Allah is about fulfilling our religious obligations; even something as small as leaving a space the size of a hair can have serious consequences in the hereafter. Therefore, we should strive to fulfill our religious obligations with utmost care and attention so that we may be rewarded in both worlds.