CLAIM: James writes, “Let endurance have its perfect result, so that you may be perfect and complete, lacking in nothing” (Jas. 1:4). Does this mean that Christians can reach a state of sinless perfection?
RESPONSE: Our hermeneutic needs to be grammatical and historical, but it also needs to be intelligible. Such an interpretation completely strains intelligibility, because if Christians can reach a state of sinless perfection, then I’ve never met a Christian before!
The Bible teaches that none of us will reach a state of sinless perfection this side of eternity. John writes, “If we say that we have no sin, we are deceiving ourselves and the truth is not in us” (1 Jn. 1:8). James writes, “For we all stumble in many ways” (Jas. 3:2), referring to Christian believers. Paul speaks of the flesh and Spirit battling one another in the life of the Christian (Gal. 5:17), and he himself experienced this personal struggle with sin (Rom. 7:17).
The Greek word for “perfect” is teleios. It can also be translated as “completeness,” “maturity,” or “integrity” (c.f. 1 Cor. 2:6; 14:20; Eph. 4:13; Heb. 5:14). The word probably means fulfillment or completeness of God’s work in our lives. In other words, when we go through trials and suffering, this produces transformation in our lives.
In the beginning of the verse, note that we are not perfect, but that God can use suffering to have a perfect result in the development of our character. Hodges writes, “Too often we are so eager to escape our difficulties that we seek mere relief from the trial, rather than to gain every possible spiritual benefit from it. If we say, ‘I cannot endure any more of this,’ then God’s work of endurance within us is not perfect (Greek: teleios, ‘complete’).” This is a great promise to endure during these times of suffering.
 Hodges, Z. C., Farstad, A. L., & Wilkin, R. N. (1994). The Epistle of James: proven character through testing (pp. 19–20). Irving, TX: Grace Evangelical Society.