This scene shows Mr.white being stubborn because Sergeant-Major Morris warned him about the monkey paw.
A visitor came to the Whites home to adress them that Herbert had died at Meg and Maws from the machinery. In return for his death the Whites got 200 pounds.
Mrs.White was in a lot of pain because of the death of Herbert, so she wanted her husband to wish him alive again. Mr.White knew the consequences of it and tried to argue with his wife thta he can not, but he wound up doing it anyways.