The following is from the valuable blog, "Between Two Worlds," and the specific post, Lloyd-Jones: Focusing on What Really Matters:
D. Martyn Lloyd-Jones, commenting on Philippians 1:10 ("that you may approve what is excellent," or "that you may have a sense of what is vital"):
The difficulty in life is to know on what we ought to
concentrate. The whole art of life, I sometimes think, is the art of knowing
what to leave out, what to ignore, what to put on one side. How prone we are to
dissipate our energies and to waste our time by forgetting what is vital and
giving ourselves to second and third rate issues. Now, says Paul, here you are
in the Christian life, you are concerned about difficulties, about oppositions
and about the contradictions of life. What you need is just this: the power to
concentrate on that which is vital, to leave out everything else, and to keep
steadily to the one thing that matters.
- The Life of Joy: Philippians, vol. 1, pp. 54-55.