Read almost any book on special operations and you will see perseverance in action, as it is a mental requirement for anybody who wants to serve in that capacity. These men keep pushing forward despite all the different obstacles and setbacks in their way. The role of Perseverance in survival is a major one and if you do not set your mindset to Persevere when put in a survival situation you will die.
Having a STRONG MINDSET is not something that happens overnight. It is something that you must work at every day. In your work, in the Gym, in your relationships, and in all the little things you do. Perseverance is but one trait of a Strong Mindset. You must live with the intention of developing a strong mind, it will not happen unless you put in the work. Lets look at a very simple example of perseverance in action: Exhausted on the last set of your workout? Add 5 lbs and push through it. Even if you are not successful in completing the whole set you will have grown mentally by making that decision in your head to persevere and finish strong.