A.T. Robertson Commentary James 1:15

"Then the lust, when it hath conceived, beareth sin: and the sin, when it is fullgrown, bringeth forth death." — James 1:15 (ASV)

Then (ειτα). The next step.

The lust (η επιθυμια). Note article, the lust (verse 14) which one has.

When it hath conceived (συλλαβουσα). Second aorist active participle of συλλαμβανω, old word to grasp together, in hostile sense (Acts 26:21), in friendly sense of help , in technical sense of a woman taking a man's seed in conception (Luke 1:24), here also of lust (as a woman), "having conceived." The will yields to lust and conception takes place.

Beareth sin (τικτε αμαρτιαν). Present active indicative of τικτω to bring forth as a mother or fruit from seed, old verb, often in N.T., here only in James. Sin is the union of the will with lust. See Ps 7:14 for this same metaphor.

The sin (η αμαρτια). The article refers to αμαρτια just mentioned.

When it is full-grown (αποτελεσθεισα). First aorist passive participle of αποτελεω, old compound verb with perfective use of απο, in N.T. only here and Lu 13:32. It does not mean "full-grown" like τελειοω, but rather completeness of parts or functions as opposed to rudimentary state (Hort) like the winged insect in contrast with the chrysalis or grub (Plato). The sin at birth is fully equipped for its career (Romans 6:6; Colossians 3:5).

Bringeth forth death (αποκυε θανατον). Late compound (κυεω to be pregnant, perfective use of απο) to give birth to, of animals and women, for normal birth (papyrus example) and abnormal birth (Hort). A medical word (Ropes) rather than a literary one like τικτω. The child of lust is sin, of sin is death, powerful figure of abortion. The child is dead at birth. For death as the fruit of sin see Ro 6:21-23; 8:6. "The birth of death follows of necessity when one sin is fully formed" (Hort).