Mosiah 4:27 And see that all these things are done in wisdom and order; for it is not requisite that a man should run faster than he has strength. And again, it is expedient that he should be diligent, that thereby he might win the prize; therefore, all things must be done in order.
I know a few runners. They could easily outrun me in any race. They are better able to keep up a fast pace for a longer distance. I, on the other hand, am a slow creature. I wasn't built for speed. Just look around the animal kingdom for examples of animals that are and are not made for speed. It's not just an excuse- some really are built to run faster. (Picture a cheetah versus a hippo...)
That's not to say that I couldn't run faster than I do now. I could get serious about training and go out running every day to increase my speed and stamina. Let's be honest, though- I'll never be an olympic contender!
But this got me thinking about what it really means to run faster than I have strength for. If I was a fast "runner", I could keep up a strenuous pace of activities. I could probably schedule more items in a day than I do now. But because I am a slow "runner" (technically just a walker) I have to pace myself and be careful not to overdo it. If I let myself get caught up in comparing how far ahead someone else is running, I'm probably going to get discouraged and want to give up.
If I'm wise and take into account my levels of spiritual fitness, energy, and health, I'll push myself a little beyond what I'm comfortable with, but not so far that I pull a muscle, strain a tendon, or otherwise injure myself (spiritually speaking.) By not being content to just be a slow walker, I can eventually strengthen myself to become a runner.
It doesn't matter what our level of fitness is in regards to the gospel. What matters is that we are diligent in moving forward, working to increase our strength and speed, while being careful to maintain that health and balance that will bring optimum results. We cannot run faster than we have the strength to, but we can steadily increase that strength and become more fit to do the work of God.
We might as well enjoy the strength we have and take advantage of it while we can. As we age we will become slower. Time takes it's toll on even the fittest of bodies. We need to be prepared for the day that our strength will only allow a shuffling walk, and know that God is just as satisfied with the efforts of the feeble as He is with the fit. God gives out prizes to those who finish, not just those who finish first!