And he said to all, "If anyone would come after me, let him deny himself and take up his cross daily and follow me.
For whoever would save his life will lose it, but whoever loses his life for my sake will save it.
For what does it profit a man if he gains the whole world and loses or forfeits himself? For whoever is ashamed of me and of my words, of him will the Son of Man be ashamed when he comes in his glory and the glory of the Father and of the holy angels.

JC Ryle writes: We learn, for one thing, the absolute necessity of daily self-denial. We ought every day to crucify the flesh, to overcome the world, and to resist the devil. We ought to keep under our bodies, and bring them into subjection. We ought to be on our guard, like soldiers in an enemy's country. We ought to fight a daily battle, and war a daily warfare. The command of our Master is clear and plain: "If any man will come after Me, let him deny himself, and take up his cross daily, and follow Me." 

These verses also teach the unspeakable value of the soul. A question is asked, which admits of only one answer—"What is a person advantaged if that person gain the whole world an lose his or her soul", meaning the soul is cast into hell.

The possession of the whole world, and all that it contains, would never make anyone happy. Its pleasures are false and deceptive. Its riches, rank, and honours, have no power to satisfy the heart. So long as we have not got them they glitter, and sparkle, and seem desirable. The moment we have them we find that they are empty bubbles, and cannot make us feel content. And, worst of all, when we possess this world's good things, to the utmost bound of our desire, we cannot keep them. Death comes in and separates us from all our property forever. Naked we came upon earth, and naked we leave, and of all our possessions we can carry nothing with us. Such is the world, which occupies the whole attention of millions! Such is the world, for the sake of which millions are every year destroying their souls!

J.C. Ryle Expository Thoughts on the Gospels - Gospel of Luke