The shared purpose of both the fable by Aesop and the excerpt from Shakespeare’s Romeo and Juliet is to instruct with a moral lesson.
In Aesop's fable, the moral revolves around the dangers of trying to avoid fate or attempting to escape one's destiny, as the prince's effort to escape his fate leads to his unfortunate demise. Similarly, in the excerpt from Romeo and Juliet, the themes of fate and the consequences of foreboding dreams illustrate the idea that our actions can lead to inevitable outcomes, teaching a lesson about the interplay between fate and free will. Both texts ultimately highlight how attempts to control one's fate can lead to unintended and tragic consequences.