James 5:20

Let him know
And observe it for his encouragement:

that he which converteth a sinner from the error of his way;
who is the instrument of restoring a backsliding professor, for such an one is meant by a sinner, and not a profane person; or of turning a poor bewildered believer, who is got out of the way of truth and holiness, into the right way again; or of convincing him of the error of his way, whether it be in point of doctrine, or of duty; and so of bringing him to the fold of Christ again, from whence he has strayed:

shall save a soul from death;
not efficiently, but instrumentally, as in ( 1 Timothy 4:16 ) for otherwise Christ is the only Saviour; and he will be the means of saving "a soul", which is of more worth than a world; and that from death, the second death which lies in the separation of the soul from God, and in a sense of his wrath; which apostasy threatens with, and leads unto, if grace prevents not. The Alexandrian copy and others, and the Vulgate Latin version read, "his soul"; but the common reading is more emphatic; the Syriac and Arabic versions render it, "his own soul"; and the Ethiopic version, "himself", as respecting him that is the instrument of the conversion of the other, and not the person converted:

and shall hide a multitude of sins;
either "his own", as the same versions read; and then the sense is, he shall be blessed with a discovery and application of the forgiveness of all his sins, though they have been many and great; or rather the sins of the person converted. Sin is only covered by the blood and righteousness of Christ; and thereby it is so covered, as not to be seen by the eye of vindictive justice and in such manner as that the persons of those who are covered therewith are all fair, without fault and unreproveable in the sight of God; and though their sins are many, even a multitude, they are blotted out as a thick cloud, and are abundantly pardoned; yea, all their sins are covered, be they ever so many, for God forgives all trespasses, for Christ's sake; and the blood of Christ cleanses from all sin, and his righteousness justifies from all: and whoever is an instrument of bringing a backslider to a sense of the evil of his ways, and to true repentance for the same; as he, upon such repentance, has his iniquities caused to pass from him, or, in other words, to be covered, as from the sight of God, so from his own; he may be said to be the instrument of this also.