In the book "The Crossover" by Kwame Alexander, when Dad says, "Filthy talking to your brother right now would be like pushing water with a rake," he means that it would be pointless or ineffective to try to talk to his son in an angry or confrontational manner. Using strong language or being aggressive with words would not be helpful or productive in getting through to his son, just like trying to push water with a rake would be an impossible task.
