Jamieson, Fausset and Brown on James 1:11

11. Taken from Is 40:6-8.

heat--rather, "the hot wind" from the (east or) south, which scorches vegetation (Lu 12:55). The "burning heat" of the sun is not at its rising, but rather at noon; whereas the scorching Kadim wind is often at sunrise (Jon 4:8) [Middleton, The Doctrine of the Greek Article]. Mt 20:12 uses the Greek word for "heat." Is 40:7, "bloweth upon it," seems to answer to "the hot wind" here.

grace of the fashion--that is of the external appearance.

in his ways--referring to the burdensome extent of the rich man's devices [Bengel]. Compare "his ways," that is, his course of life, Jas 1:8.