This quote from "Watership Down" by Richard Adams reflects the themes of sacrifice and loyalty present in the story. It emphasizes the selfless nature of characters who are willing to give their lives for those they love, such as a doe for her kittens or a captain for his leader. This illustrates the deep bonds that exist within their community and the significance of duty and honor in their relationships.

Moreover, the quote highlights the notion of inevitability in life and death. The phrase "what is, is what must be" suggests that the sacrifices made are not negotiable; they arise from a natural order or moral obligation. This perspective on fate and survival underscores the harsh realities that the characters face in their quest for safety and belonging in a world that often demands such sacrifices.