Let the lowly brother boast in his exaltation, and the rich in his humiliation, because like a flower of the grass he will pass away. For the sun rises with its scorching heat and withers the grass; its flower falls, and its beauty perishes. So also will the rich man fade away in the midst of his pursuits. (James 1:9-11)
In addition to writing his book full of imperative statements, James also relies heavily upon contrasting elements. In 1:9-11, he contrasts the "lowly" against the "rich." He challenges them with action in the present, but does so by previewing the future.
We must take note that James' emphasis is not upon their bank accounts; it's upon their attitudes. The lowly (humble, 4:1-10) brother acknowledges the utmost importance of God in all that he does. He will be exalted in the life to come. The rich are not necessarily all who are financially blessed, but those whose pride and boasting are founded upon their possessions--and the status in life they provide (cf, 5:1-6).
When Jesus came to earth, he turned it upside down--especially for the Jews. He didn't come with the purpose of doing away with rich and poor designations while on earth. He came to show that man will not be judged by their political, socio-economic, or even religious status. He will judge all men by their hearts (Matt. 5:8).
To illustrate this reversal of standing, James turns to nature in a way where first century Palestinians could not misunderstand him. He compares those who are rich to the grass and flowers of the land. Though beautiful, they don't last forever. Though beautiful, they don't withstand the elements of heat. Likewise, he says, the rich man will perish "in the midst of his pursuits."
These few verses are not James' final word on proper attitudes, partiality, riches, and the brevity of life. He further develops those themes throughout his letter. But we cannot gloss over these specific instructions. Humble and lowly Christians should take courage from their relationship with the Creator of the universe; Christians who choose to build their lives on possessions should repent. Soon, there will be a day when those possessions are nothing but dust.
Everyone then who hears these words of mine and does them will be like a wise man who built his house on the rock. And the rain fell, and the floods came, and the winds blew and beat on that house, but it did not fall, because it had been founded on the rock. And everyone who hears these words of mine and does not do them will be like a foolish man who built his house on the sand. And the rain fell, and the floods came, and the winds blew and beat against that house, and it fell, and great was the fall of it. (Matt. 7:24-27)