In the context of M.C. Beaton's "Death of a Poison Pen," the quote by William Shakespeare highlights the importance of moving on from situations that are beyond remedy. The phrase underscores that dwelling on the past can lead to unnecessary sorrow, suggesting that acceptance is crucial in overcoming grief. It reminds us that focusing on what we cannot change often hinders our ability to find peace.

This perspective is central to understanding the characters and their struggles within the narrative. The story addresses themes of loss and the challenge of letting go, aligning with Shakespeare's wisdom. Ultimately, it encourages readers to reflect on their own experiences with grief and the importance of finding closure.