Greitens argues that true resilience comes from taking positive actions rather than merely thinking positively. He emphasizes that while positive thinking can be helpful, it is the actions we take that ultimately shape our lives and help us overcome obstacles. This idea encourages readers to focus on what they can do to improve their situations rather than just hoping for the best.

One of the central themes of "Resilience" is the importance of mental toughness and discipline. Greitens shares techniques and strategies to build mental strength, such as setting goals, maintaining focus, and pushing through discomfort. This theme is crucial because it highlights that resilience is not an innate trait but a skill that can be developed through consistent effort and practice.

Greitens stresses the significance of having a sense of purpose and meaning in life. He believes that understanding one's purpose can provide the motivation and direction needed to navigate through tough times. This idea is particularly powerful as it encourages readers to reflect on their values and passions, helping them to find a deeper sense of fulfillment and drive in their daily lives.