The Prophet's (Sallallaho alaihe wasallam) reprimand on the Sahabah's Laughing
Once, the Prophet (Sallallaho alaihe wasallam) came to the musjid for Salaat, where he noticed some people laughing and giggling. He remarked:
"If you remembered your death, I would not see you like this. Think of your death often. Not a single day passes when the grave does not call out: 'I am a wilderness', I am a place of dust, I am a place of worms'. When a Mo'min is laid in the grave, it says; 'Welcome to you. It is good of you to have come into me. Of all the people walking on the earth, I liked you best.
Now that you have come into me, you will see how I entertain you'. It then expands as far as the occupant can see. A door from Paradise is opened for him in the grave and, through this door, he gets the fresh and fragrant air of Paradise. But when an evil man is laid in the grave it says; 'No word of welcome for you. Your coming into me is very bad for you.
Of all the persons walking on the earth, I disliked you most. Now that you have been made over to me, you will see how I treat you!' It then closes upon him so much that his ribs of one side penetrate into the ribs of the other. As many as seventy serpents are then set upon him, to keep biting him till the Day of Resurrection. These serpents are so venomous that if one of them happened to spurt its venom upon the earth, not a single blade of grass would ever grow."
After this, the Prophet (Sallallaho alaihe wasallam) said:
"The grave is either a garden of Paradise or a pit of Hell."
Fear of Allah is the basic and essential qualification of a Muslim. The Prophet (Sallallaho alaihe wasallam) advised the believers to remember death, off and on, and to keep the fear of Allah ever present in their hearts.