The following is an excerpt from The MacArthur New Testament Commentary on James 5 .

My brethren, if any among you strays from the truth and one turns him back, let him know that he who turns a sinner from the error of his way will save his soul from death and will cover a multitude of sins.(James 5:19–20)

James defines the wanderer from sound doctrine and godly living as a sinner—a word used in Scripture of the unregenerate (cf. Prov. 11:31; 13:6, 22; Matt. 9:13; Luke 7:37, 39; 15:7, 10; 18:13; Rom. 5:8; 1 Tim. 1:9, 15; 1 Pet. 4:18), not believers. The term sinner frequently describes hardened unbelievers, those who openly, defiantly disregard God’s law; those whose evil character is apparent to everyone; those whose wickedness is common knowledge. Genesis 13:13 described the men of Sodom as “wicked exceedingly and sinners against the Lord.” The opening verse of Psalms declares, “How blessed is the man who does not walk in the counsel of the wicked, nor stand in the path of sinners, nor sit in the seat of scoffers!” (Ps. 1:1). Verse 5 of that same psalm adds, “The wicked will not stand in the judgment, nor sinners in the assembly of the righteous.” Sinners are defined in Psalm 51:13 as those who need to be converted to God, while Proverbs 11:31 contrasts the wicked sinner with the righteous.

In the New Testament the term sinner invariably describes those outside the kingdom of God. Jesus declared in Matthew 9:13, “I did not come to call the righteous, but sinners.” Sinners are those whose repentance causes joy in heaven (Luke 15:7, 10); it was when he cried out “God, be merciful to me, the sinner!” that the tax collector “went to his house justified” (Luke 18:13–14). It was “while we were yet sinners” that “Christ died for us” (Rom. 5:8); indeed, “It is a trustworthy statement, deserving full acceptance, that Christ Jesus came into the world to save sinners” (1 Tim. 1:15).

A sinner, then, is someone who is without God and Christ, and so in need of salvation; it is a word of characterization. The apostle John writes, “The one who practices sin is of the devil. … No one who is born of God practices sin” (1 John 3:8, 9). While Christians may sin, sin will not be their continual, unbroken practice; it will not characterize their lives. A sinner, on the other hand, is one who continually, habitually practices sin. Such people John declared to be children of the devil, not of God.

Realizing the terrible fate that awaits unrepentant sinners should motivate believers to call to salvation those who stray from the truth. Nothing less than each person’s eternal soul is at stake—his most priceless possession (cf. Mark 8:36–37). Psuche (soul) refers to the whole person (the Septuagint uses it in Gen. 2:7), particularly the inner, immortal person who lives in the mortal body.

The threat facing the soul is death—eternal hell, the second death, the final state of the unrepentant sinner (cf. Matt. 13:40, 42, 50; 25:41, 46; Mark 9:43–49; 2 Thess. 1:8–9; Rev. 20:11–15; 21:8). God declared in Ezekiel 18:4, “The soul who sins will die” (cf. v. 20), while Jesus warned the unbelieving Jews, “I go away, and you will seek Me, and will die in your sin; where I am going, you cannot come” (John 8:21; cf. 8:24). The ultimate end of sin, as James noted in chapter 1 of his epistle, is that it “brings forth death” (1:15). In the oft-quoted words of the apostle Paul, “the wages of sin is death” (Rom. 6:23). In one of the most terrifying passages in Scripture, the apostle John wrote, “But for the cowardly and unbelieving and abominable and murderers and immoral persons and sorcerers and idolaters and all liars, their part will be in the lake that burns with fire and brimstone, which is the second death [physical death being the first death]” (Rev. 21:8; cf. 20:11–15; Isa. 66:24; Dan. 12:2; 2 Thess. 1:8–9). It is an often overlooked truth that Jesus spoke more of hell than He did of heaven.

Those with false faith, who have chosen their own way over God’s, must heed the warning of Proverbs 14:12 or be damned: “There is a way which seems right to a man, but its end is the way of death.” The deeply serious threat the sinner faces is spiritual death—eternal separation from God in hell.

Save translates sozo, the most common New Testament word for salvation. In four of its five uses in James it refers to salvation (cf. 1:21; 2:14; 4:12; in 5:15 it refers to restoring weak, struggling Christians). Turning to God in repentance results in salvation; He will then cover the multitude of sins the repentant sinner has committed. In Psalm 32:1 David exclaimed, “How blessed is he whose transgression is forgiven, whose sin is covered!” The writer of Psalm 85 offered the following words of praise to his forgiving God: “You forgave the iniquity of Your people; You covered all their sin” (v. 2).

God has granted to all believers the ministry of reconciling wandering souls to Himself. When the evidence indicates a professed believer’s faith is not real, true Christians, knowing the terrible threat of eternal death that person faces, must make it their goal to turn him back from his sin to genuine saving faith in God.

By so doing they will exhibit true wisdom, for “he who is wise wins souls” (Prov. 11:30).