In order to endure there has to be something pulling and distracting from something. Deep endurance does not happen without the opposite of the goal pulling in a different direction. Distractions are everywhere. Distractions are the root cause of failure. Distractions need to me fought against through behaviors, mindsets, and ultimately endurance.
Living with strength and not living in fear or cowardice is a difficult and painful process. To endure, someone has to have unchangeable beliefs. A person has to have internal fortitude that is not shakable.
Certainty of the goal, the truth, and the process creates the foundation for endurance. Without endurance success will not be found.