Just read about the Alexander the Great. He struggled greatly to maintain the loyalty and motivation of his men. He ultimately could not gain their motivation when they saw no end to his appetite for conquest but he could use his own personal example to drive the group. He took enormous risks in order to achieve. His risk taking ultimately set the stage for his demise.
The thing that distinguishes the excellent athlete or warrior from the average is a determination which causes them to take themselves to the very limits of their abilities. In the movie miracle which chronicles the U.S. hockey teams efforts to beat the Russian team, the coach pushes the team to be the best conditioned. "Legs feed the wolf", is his motto and so the athletes skate until they are all skated out. Injury and trouble does not mean quit. There is a time to count the costs, but if the cause is righteous and blessed from heaven then there is no stopping. I know working in the kingdom of God is different than competing in athletics or on the battlefield. However, pushing myself to my limits is exactly what I need to be able to do.
"I press on to the prize..."