So the rich brother is to be reminded of his humiliation, "in that he is made low," placed on a level with the "lowly brother." They meet on the level in Christ. Each is as high and as low as the other--no more, no less. The rich man is not to glory over the poor man, nor is the poor brother to cringe in the presence of the rich brother. This is the democracy of faith, the universality of Christ.
The rich brother is in constant peril of pride of possession, and so James reminds him of the fate of the beautiful flower of the grass which springs up quickly and withers before the burning heat and falls off. It is a striking adaptation of the language of Isaiah (40:6-8), using the imagery for another purpose. 1 Peter 1:24 says: "All flesh is as grass, and all the glory thereof as the flower of grass." Christ brings all men to their true level, the common humanity in us all, the sonship in him that makes us heirs of heaven. Moffatt changes "his high estate" to "when he is raised," and "in that he is made low" to "in being lowered." He seems to understand that James refers to the possible ups and downs of life. It will be easy for the lowly brother in that case to rejoice when he becomes rich; but how about the rich brother when he becomes poor?
Plummer (_in loco_) refuses to see a "brother" at all in the rich man, but only one of the rich Jews who oppressed the early Christians, as in James 5:1-6. But that gives an Ebionitic tone to the epistle. James does indulge in irony, but he is apparently sincere in his picture here. The rich brother will fade away in his goings, as if James has in mind a salesman whose business dries up like a flower. Riches truly have wings and fly away. They are sweet like the rose but soon vanish from us forever.
James powerfully sketches the natural history of temptation if yielded to and the glory of victory if overcome. The other sense (temptation) of the word used for trial in 1:2 occurs here. Moffatt indeed takes trial as the idea in 1:12 also (so does Hort _in loco_), but certainly in verse 13 we have to say "temptation." It is most likely that the idea of temptation is present in 1:12. Here James returns to the discussion of the other side of the blessing of trials, namely, the blessing of temptation endured. As a matter of fact, he has not really digressed from the subject. He merely discusses one aspect.