1 Corinthians 9:24 "Do you not know that in a race all the runners run, but only one gets the prize? Run in such a way as to get the prize."
I played volleyball during high school and one thing I learned while playing is that you can practice all the time and have a lot of skill, but when it came down to the game, it depended largely on mental discipline. One person's attitude had the power to drag the entire team down. Discouragement could quickly be seen in performance. And when we were defeated in the mind, we were also defeated on the court. If we were facing an opponent and accepted defeat or doubted that the victory would be ours, we would give up far sooner then we would've if we would've played to win. It was important to intentionally prepare our mind before a game.

The same is true in our spiritual race. I can attend church, read the Bible, pray and do all of these "spiritual excercises," but if I do not discipline my mind and decide to run the race with all that I am, I will quickly become discouraged and loose heart. I am not saying that that I shouldn't do these "spiritual excercises" because, like it is in sports, I can discipline my mind all that I want but I will get nowhere if my body has not been discipined. I am only pointing out that the outward discipline must be followed by the mental discipline. When I decide in my mind to run for the prize, my outward actions will follow.

As I am here in training, we are constantly surrounded by excercises to train us. We study the Bible, pray, go to class, attend church bi-weekly, worship, read wholesome books, etc. All of this is important, but will be meaningless if not accompanied by a mental discipline and a decision to run as for the prize. A runner who has the prize in mind is not half hearted, he is devoted and has his eyes fixed on one thing. 

"...let us run with perseverance the race marked out for us. Let us fix our eyes on Jesus, the author and perfecter of our faith, who for the joy set before him endured the cross, scoring it's shame, and sat down at the right hand of God." (Hebrews 12:1-2)

"You will keep in perfect peace him whose mind is steadfast, because he trusts in you." (Isaiah 26:3-4).