Verse 19: Brethren, (Matt. 18:15) if any of you do err from the truth, and one convert him…
[If any…do err from the truth] That is, from the right rule of living, which embraces these two things, a sound faith, and holy conversation (Estius, similarly Tirinus); or, from that manner of life that the Gospel prescribes, which is by way of eminency called the truth, Romans 15:8; Galatians 2:5, 14; 3:1; 5:7; James 1:18; 1 Peter 1:22 (Grotius). He had taught them, that either they themselves might ask from others, or furnish for others, prayers and help in their calamities, for the healing, not only of bodies, but also of souls. He commends this Christian duty in this place from the best effects of that (Gataker).
The truth; the truth of God revealed in the gospel as the complete rule of faith and life: see the gospel called the truth by way of eminency, James 1:18; Galatians 2:5, 14; 3:1; 5:7; Ephesians 1:13; 1 Peter 1:22.
[And, etc., καὶ ἐπιστρέψῃ, etc.] And one convert, etc. (Beza, Piscator, Vulgate), that is, recall to the way (Beza), that is, by applying the helps instituted by God for conversion (Estius); by praying, teaching (Tirinus, thus Estius), rebuking, correcting (Estius), drawing by example or good deeds (Tirinus). If one by good counsel lead him away from unrighteousness, from envy, from hatred, from a readiness to swear, and similar things. It is the mystical sense of the precept which is found in Deuteronomy 22:1 (Grotius).
And one; any one, minister or private believer, who may be an instrument in the conversion of others; though one acts by way of authority, the other by way of charity, yet both out of duty. Convert him; viz. ministerially or instrumentally, in subordination to God. The work is his, Ephesians 2:10, but often is ascribed to the instruments acting under him, and using means appointed by him, and by which he works, Acts 26:18.
Verse 20: Let him know, that he which converteth the sinner from the error of his way (Rom. 11:14; 1 Cor. 9:22; 1 Tim. 4:16) shall save a soul from death, and (Prov. 10:12; 1 Pet. 4:8) shall hide a multitude of sins.
[From the error of his way] That is, of his depraved life, manners, and actions (Menochius). Every sinner errs in judgment of mind (Estius, Gataker), that is, from the way that God has prescribed to him, and from the way that alone leads to the goal and end intended by himself; and that from ignorance either simple or affected (Gataker).
Of his way; of his life and actions, which is contrary to the way which God hath prescribed.
[He shall save a soul, etc.] A manuscript adds his (Grotius). But soul, posited absolutely, has emphasis (Estius). It shall be the cause of salvation to him that had sinned. A similar expression in Romans 11:14; 1 Timothy 4:16; Jude 23. Now, he is rightly said to be rescued from death, not only one who at first is led to Christianity, but also who is led back from a vicious life to a life agreeable with Christianity. See an example in 1 Corinthians 3:15 (Grotius). There are as many arguments as words. He shall save: In his own way he is a Savior, both by bringing the word of salvation, Acts 13:26, and by showing the way of salvation, Acts 16:17; Luke 1:79. Σωτῆρα, etc., I consider him who shows to me my errors and sins, to be my Savior, more than him who heals my sick body, says Galen (Gataker). A soul, that is, a man (Gataker, similarly Piscator), the most noble creature, and the soul, the most excellent part of man, and what is best in the soul, namely, life (Gataker); from death, even eternal death (Estius, Gataker). And hence this office of saving others is the most noble. For even the rescuing of a beast fallen into a pit is a work so pleasing to God, that He wills even His own worship to be subordinated to it, Matthew 12:7, 11 (Gataker).
Shall save; men are said to save in the same way as to convert, viz. instrumentally. A soul; the soul of him that is thus converted, 1 Timothy 4:16: soul for person, as James 1:21. From death: eternal death, unto which he was hastening while he continued in the error of his way, which led him toward destruction.
[And, etc., καὶ καλύψει, etc.] Καλύπτειν, כָּסָה, to cover, is to forgive, as it appears in Psalm 32:1, they are covered, etc. In this sense, a wise man is said to cover the sins of others, in the Talmud, in the title of Bathra 8 (Grotius). And he shall conceal, or cover (that is, there shall be an occasion that they be covered [Drusius]; or, he shall bring it to pass that God covers [Piscator]) a multitude of sins (Erasmus, Vatablus, Drusius, thus Beza, Piscator, etc.). As a testimony, he cites this out of Proverbs 10:12 (certain interpreters out of Gataker). Rather, he alludes to that (Calvin): for Solomon and James speak of diverse matters (Gataker); the former speaks of covering sins among men, the latter of completely erasing them before God (Calvin, similarly Gataker). Now, by sins here he understands, either, 1. his own (Bede in Estius, Vorstius, Hammond, Aquinas, Rickelius, Fevand., Origen, Damascenus in Gataker): that is to say, hence the greatest advantage shall fall, not to the other, whose soul shall be saved; but even to himself (Gataker), whose sins, although they be many and grievous, shall be more readily covered before God (Vorstius, thus Gataker): this work is so pleasing to God that He grants the pardon of sin to the one effecting it, if he himself repents (Hammond). Objection: Thus a man might be said to cover his own sins, but this is the work of God alone (certain interpreters in Hammond). Indeed, he is able properly to cover neither his own nor another’s sins, but figuratively, as it is able to be taken of both (Hammond). Or, 2. another’s (Vorstius), namely, the sins of him whom he converted (Estius, Gataker): that is to say, he shall be responsible for the forgiveness of many sins to him (Gataker): He shall bring it to pass that God would conceal those former sins of the one now converted, and, as it were, place them out of His sight (Grotius, Gataker), Numbers 23:21; Psalm 32:1, 5; Isaiah 38:17; not in such a way that He does not discern them, but rather that He does not regard or avenge them. He who repents of sin is almost innocent, Seneca. God altogether remits to the penitent all their sins, Colossians 2:13; 1 John 1:7, 9 (Gataker). This interpretation is not satisfying. For thus this latter member, he shall cover sins, is included in the former, he shall save a soul, neither does it add anything to it (Hammond).
And shall hide a multitude of sins; in the same sense as before he is said to convert and save his soul, viz. in being instrumental to bring him to faith and repentance, upon which God pardons, i.e. hides his sins, (Psalm 32:1,) though not from the eye of his omniscience, yet from the eye of his vindictive justice, and so as not to bring them forth in judgment against him.
 Greek: Ἀδελφοί, ἐάν τις ἐν ὑμῖν πλανηθῇ ἀπὸ τῆς ἀληθείας, καὶ ἐπιστρέψῃ τις αὐτόν,
 Greek: γινωσκέτω ὅτι ὁ ἐπιστρέψας ἁμαρτωλὸν ἐκ πλάνης ὁδοῦ αὐτοῦ σώσει ψυχὴν ἐκ θανάτου, καὶ καλύψει πλῆθος ἁμαρτιῶν.
 Thus Codices Sinaiticus and Alexandrinus.
 Psalm 32:1: “Blessed is he whose transgression is forgiven, whose sin is covered (כְּס֣וּי חֲטָאָֽה׃; ὧν ἐπεκαλύφθησαν αἱ ἁμαρτίαι, in the Septuagint).”
 John Damascenus (c. 676-c. 760) was a monk of St. Sabas, near Jerusalem. He is remembered for his piety of life, writings, and compilation of chants in the eastern style; and, due to his defense of icons and his summary of the faith of the Fathers (Fountain of Knowledge), he is regarded by many as the last of the Eastern Fathers.
 Agamemnon 242.