Isaiah 40:6
4 Every valley must be elevated and every mountain and hill leveled. The rough terrain will become a level plain, the rugged landscape a wide valley. 5 The splendor of the Lord will be revealed, and all people will see it at the same time. For the Lord has decreed it.” 6 A voice says, “Cry out!” Another asks, “What should I cry out?” The first voice responds: “All people are like grass, and all their promises are like the flowers in the field. 7 The grass dries up, the flowers wither, when the wind sent by the Lord blows on them. Surely humanity is like grass. 8 The grass dries up, the flowers wither, but the decree of our God is forever reliable.”
James 1:10
8 since he is a double-minded individual, unstable in all his ways. 9 Now the believer of humble means should take pride in his high position. 10 But the rich person’s pride should be in his humiliation because he will pass away like a wildflower in the meadow. 11 For the sun rises with its heat and dries up the meadow; the petal of the flower falls off and its beauty is lost forever. So also the rich person in the midst of his pursuits will wither away. 12 Happy is the one who endures testing because when he has proven to be genuine, he will receive the crown of life that God promised to those who love him.
Notes and References
"... The subject of 1:10b, 'because the rich will disappear,' is implied. Again, there is some matter of disagreement. If the 'rich' is a 'brother,' then the implied subject could be the 'riches' themselves rather than the 'rich' himself. Our exegesis up to this point favors the 'rich' as the implied subject. The word 'because' supports such an interpretation, since it gives the reason that James can (ironically) claim that the rich person can 'boast' (implied and ironical) in his humiliation (ironical). Why? Because he, the person, will perish. Such a person, we are contending that James is saying, 'will disappear like a flower in the field.' Here James draws on a stock image from both experience in the Land of Israel and in the Scriptures. Three texts come to mind immediately: Psalms 90:3-6 and 103:15-16 and Isaiah 40:6-8 ..."
McKnight, Scot The Letter of James (p. 189) William B. Eerdmans Publishing Company, 2011