why is the following passage from The Devil’s Arithmetic is a prime example of dramatic irony.

why is this dramtic irony? “Please, Rabbi,’ she pleaded, ‘we must do something. And quickly. I know where they are taking us. I am from the future. Please.’ Rabbi Boruch cleared his throat before speaking. ‘All children are from the future. I am from the past. And the past tells us what we must do in the future….So you must listen to me when I tell you that what we must do now is pray.”