{The tongue is a fire} (h(8820)gl(9373)sa pur). So necessarily
since there is no article with pur (apparently same word as
German _feuer_, Latin _purus_, English _pure, fire_). This
metaphor of fire is applied to the tongue in  Pr 16:27  26:18-22 ; Sirach 28:22. {The world of iniquity} (ho kosmos t(8873)
adikias). A difficult phrase, impossible to understand according
to Ropes as it stands. If the comma is put after pur instead of
after adikias, then the phrase may be the predicate with
kathistatai (present passive indicative of kathist(886d)i, "is
constituted," or the present middle "presents itself"). Even so,
kosmos remains a difficulty, whether it means the "ornament"
( 1Pe 3:3 ) or "evil world" ( Jas 1:27 ) or just "world" in the
sense of widespread power for evil. The genitive adikias is
probably descriptive (or qualitative). Clearly James means to say
that the tongue can play havoc in the members of the human body.
{Which defileth the whole body} (h(8820)spilousa holon to s(936d)a).
Present active participle of spilo(935c) late _Koin(825f), verb, to
stain from spilos (spot, also late word, in N.T. only in  Eph
5:27  2Pe 2:13 ), in N.T. only here and  Jud 1:23 . Cf.  1:27 
aspilon (unspotted). {Setteth on fire} (phlogizousa). Present
active participle of phlogiz(935c), old verb, to set on fire, to
ignite, from phlox (flame), in N.T. only in this verse. See
anaptei (verse  5 ). {The wheel of nature} (	on trochon
genese(9373)). Old word for wheel (from 	rech(935c), to run), only here
in N.T. "One of the hardest passages in the Bible" (Hort). To
what does 	rochon refer? For genese(9373) see  1:23  apparently
in the same sense. Vincent suggests "the wheel of birth" (cf.  Mt
1:1,18 ). The ancient writers often use this same phrase (or
kuklos, cycle, in place of 	rochos), but either in a
physiological or a philosophical sense. James may have caught the
metaphor from the current use, but certainly he has no such
Orphic or Pythagorean doctrine of the transmigration of souls,
"the unending round of death and rebirth" (Ropes). The wheel of
life may be considered either in motion or standing still, though
setting on fire implies motion. There is no reference to the
zodiac. {And is set on fire by hell} (kai phlogizomen(8820)hupo
gehenn(8873)). Present passive participle of phlogiz(935c), giving the
continual source of the fire in the tongue. For the metaphor of
fire with gehenna see  Mt 5:22 .