Mr. White grabs the Monkey's paw from the fire out of curiosity. He impulsively wishes for 200 pounds to pay off the debt of his house. This is important to the story because we find out later that it is the reason of Herbert's death. Also, it shows that he is very careless and does not think about his decisions.
A man comes to the White's house to tell them that their son Herbert has died in the machinary and they are giving them 200 pounds for it. Mr White passes out knowing he wished for his son's death. This is important because it shows the result of Mr. White's first wish and it shows the consequences of the monkey's paw.
After Mr White wishes for Herbert to be alive again, a knocking is heard at the door. Mrs. White runs to the door to try and let her son in. Mr. White grabs the monkey's paw knowing that Herbert will look mutilated. He makes one last wish for herbert to go away. This is important because it shows that Mr. White learned his lesson and realizes that nothing good comes out of the monkey's paw.