The context is an updating of several topics the Sermon on the Mount. In this verse, Jesus is talking to an individual.
Matthew 18:15 Moreover if thy brother shall trespass against thee, go and tell him his fault between thee and him alone: if he shall hear thee, thou hast gained thy brother.
Matthew 18:15 If your brother or sister sins, go and point out their fault, just between the two of you. If they listen to you, you have won them over.
When, however, that brother yours errs, go and accuse him separating you and him alone. When of you he hears, you win that brother of yours.
Accuses people when you are alone with them.
There are four keywords here, translated as "trespass/sins," "tell him his fault/point out their fault," "between," and "gain/won them over," that Jesus only uses a few times. By looking at all his uses of these words--something the biblical translators don't seem to have done--we can get a better sense of how he uses these words: "err," "accuse," "separating," and "win."
Of course, the word translated as "trespass/sin" is one of the most interesting, if only because Jesus uses this verb so seldom, only seven times. "Sinning" was clearly not as big a factor in Jesus's teaching as it is in modern Christianity. See this article for more.
The "hear" verb also means "to be silent," which makes it kind of funny. The "you/to you" is in the form that indicates who is heard from, not what is heard about.
- CW - Confusing Word -- The "moreover" is the common word usually translated as "but" or "however."
- CW - Confusing Word -- The "if" is not the common word usually translated as "if."
- MW - Missing Word -- The word "the" before "brother" is not shown in the English translation.
- CW - Confusing Word -- The "shall" does not mean the future tense.
- OS -- Outdated Source -- The Greek word translated as "against thee" existed in the KJV Greek source but not the source we use today.
- IW - Inserted Word -- The word "and" doesn't exist in the source.
- CW - Confusing Word -- The "tell him his fault" is a simpler word meaning "accuse."
- CW - Confusing Word -- The "between" is not the common word usually translated as "between."
- CW - Confusing Word -- The "if" is not the common word usually translated as "if."
- CW - Confusing Word -- The "shall" does not mean the future tense.
- WT - Wrong Tense - The verb "hast" indicates the past perfect tense, but the tense is something that happens at a specific point in time (past, present, or future).
- MW - Missing Word -- The word "the" before "brother" is not shown in the English translation.
- MW - Missing Word -- The word "however" at the beginning of the verse is missing.
- CW - Confusing Word -- The "if" is not the common word usually translated as "if."
- MW - Missing Word -- The word "the" before "brother" is not shown in the English translation.
- IP - Inserted Phrase-- The phrase "of sister" doesn't exist in the source.
- IW - Inserted Word -- The word "and" doesn't exist in the source.
- CW - Confusing Word -- The "point out their fault" is a simpler word meaning "accuse."
- CW - Confusing Word -- The "between" is not the common word usually translated as "between."
- IP - Inserted Phrase-- The phrase "the two of" doesn't exist in the source.
- MW - Missing Word -- The word "and" is missing.
- MW - Missing Word -- The word "him" is missing.
- CW - Confusing Word -- The "if" is not the common word usually translated as "if."
- WN - Wrong Number- The word "they" is translated as plural but the Greek verb is singular.
- WT - Wrong Tense - The "have" indicates the past perfect tense, but the tense is something that happens at a specific point in time (past, present, or future).
- WN - Wrong Number- The word "them" is translated as plural but the Greek word is singular.
- IW - Inserted Word -- The word "over" doesn't exist in the source.
- MW - Missing Word -- The word "brother" is not shown in the English translation.
- MW - Missing Word -- The word "of yours" is not shown in the English translation.
Moreover - (CW) The Greek word translated as "Moreover" is usually translated as "but" since it joins phrases in an adversarial way. Since it always falls in the second position, translating it as "however" often captures its feeling better.
if - (CW) The Greek word translated as "if" indicates more of an expectation of something happening than "if" alone. More like how we use "when."
thy -- The word translated as "thy" is the genitive form of the singular, second-person pronoun, which is most commonly the possessive form. This pronoun follows the noun so "of yours."
missing "the" -- (MW) The untranslated word is the Greek definite article, which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those"). See this article for more.
brother - "Brother" is the Greek noun that means "a son of the same mother," "a kinsman," or "a colleague." It was used more generally as an indication of friendship like we use "bro" today.
shall -- (CW) This helping verb "shall" does not indicate the future tense, but that the verb describes a possibility, the subjunctive voice. A "might" or "should" in English is more appropriate, but is assumed in an "if/when/whoever/except" clause. Helping verbs are not needed in Greek since the main verb carries this information in its form.
trespass - "Trespass" is from the verb which means "to miss the mark," "to fail in one's purpose," "to err," "to be mistaken," and "to neglect."
against thee, -- (OS) There is nothing in the Greek that can be translated as "against thee" in the source we use today but it does exist in the source that the KJV translators used.
go - "Go" is a Greek verbal command that means literally "go under" or "bring under," but Christ usually uses it to mean "go away" and "depart."
and -- (IW) There is nothing in the Greek that can be translated as "and" in the Greek source.
tell him his fault - (CW) "Tell him his fault" is from a verb from the word that means "to disgrace," "to put to shame," "to cross-examine," "to expose," and "to decide a dispute." Jesus only uses it four times, and seems to used it to mean "accuse."
between - (CW) The word translated as "between" is normally an adverb meaning "in the midst" but it has a special use as the preposition meaning "between" in the sense of between two parties to an agreement or discussion. Jesus only uses this word four times, always where the sense of "separating" differentiates it from the common word translated as "between."
thee -- The word translated as "thy" is the genitive form of the singular, second-person pronoun, which is most commonly the possessive form but here is the form required by the preposition.
and -- The Greek word translated as "and" is used as the conjunction "and," but it also is used to add emphasis ("also").
him -- The word translated as "his" is the Greek word commonly translated as third-person pronouns in English.
alone: - The word translated as "alone" has the sense of being both alone and unique.
if - (CW) The Greek word translated as "if" indicates more of an expectation of something happening than "if" alone. More like how we use "when."
he -- This is from the third-person, singular form of the verb.
shall -- (CW) This helping verb "shall" does not indicate the future tense, but that the verb describes a possibility, the subjunctive voice. A "might" or "should" in English is more appropriate, but is assumed in an "if/when/whoever/except" clause. Helping verbs are not needed in Greek since the main verb carries this information in its form.
hear - "Hear" is translated from a Greek word that has the same sense as the English not only of listening but of understanding. It is not in the future tense but the tense that indicates something happening "at some point in time." Amusingly, it also means "to be silent."
thee, - The "thee" hear is in a possessive form "of you." The form of this word is who is heard from, not who is heard about.
thou-- This is from the second-person, singular form of the verb.
hast -- (WT) This helping verb "hast" indicates that the verb is the tense indicating an action completed in the past. This is not the tense of the verb here.
gained - "Gained" is from a verb that means "to gain," "to gain an advantage," "to derive profit from," and "to save yourself from." Jesus only uses it four times, consistently with a sense of "benefit" or "benefit from."
thy -- The word translated as "thy" is the genitive form of the singular, second-person pronoun, which is most commonly the possessive form. This pronoun follows the noun so "of yours."
missing "the" -- (MW) The untranslated word is the Greek definite article, which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those"). See this article for more.
brother. - "Brother" is the Greek noun that means "a son of the same mother," "a kinsman," or "a colleague." It was used more generally as an indication of friendship like we use "bro" today. -
missing "however" -- (MW) The untranslated word "however" is usually translated as "but" since it joins phrases in an adversarial way. Since it always falls in the second position, translating it as "however" often captures its feeling better.
If- (CW) The Greek word translated as "if" indicates more of an expectation of something happening than "if" alone. More like how we use "when."
your -- The word translated as "your " is the genitive form of the singular, second-person pronoun, which is most commonly the possessive form. This pronoun follows the noun so "of yours."
missing "the" -- (MW) The untranslated word is the Greek definite article, which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those"). See this article for more.
brother - "Brother" is the Greek noun that means "a son of the same mother," "a kinsman," or "a colleague." It was used more generally as an indication of friendship like we use "bro" today.
or sister -- (IP) There is nothing that can be translated as "or sister" in the Greek source.
sins- "Sins" is from the verb which means "to miss the mark," "to fail in one's purpose," "to err," "to be mistaken," and "to neglect."
go - "Go" is a Greek verbal command that means literally "go under" or "bring under," but Christ usually uses it to mean "go away" and "depart."
and -- (IW) There is nothing in the Greek that can be translated as "and" in the Greek source.
point out their fault - (CW) "Point out their fault" is from a verb from the word that means "to disgrace," "to put to shame," "to cross-examine," "to expose," and "to decide a dispute." Jesus only uses it four times, and seems to used it to mean "accuse."
just - The word translated as "just" has the sense of being both alone and unique.
between - (CW) The word translated as "between" is normally an adverb meaning "in the midst" but it has a special use as the preposition meaning "between" in the sense of between two parties to an agreement or discussion. Jesus only uses this word four times, always where the sense of "separating" differentiates it from the common word translated as "between."
the two of -- (IP) There is nothing that can be translated as "the two of " in the Greek source.
you-- The word translated as "you" is the genitive form of the singular, second-person pronoun, which is most commonly the possessive form but here is the form required by the preposition.
and -- The Greek word translated as "and" is used as the conjunction "and," but it also is used to add emphasis ("also").
him -- The word translated as "his" is the Greek word commonly translated as third-person pronouns in English.
If- (CW) The Greek word translated as "if" indicates more of an expectation of something happening than "if" alone. More like how we use "when."
they -- (WN) This is from the third-person, singular form of the verb.
listen - "Listen " is translated from a Greek word that has the same sense of "hear" in the English not only of listening but of understanding. Amusingly, it also means "to be silent."
to -- This word "to" comes from the genitive case of the following word that requires the addition of a preposition in English.
you - The form of this word is who is heard from, not who is heard about.
you -- This is from the second-person, singular form of the verb.
have -- (WT) This helping verb "have " indicates that the verb is the tense indicating an action completed in the past. This is not the tense of the verb here.
won - "Won" is from a verb that means "to gain," "to gain an advantage," "to derive profit from," and "to save yourself from." Jesus only uses it four times, consistently with a sense of "benefit" or "win."
them -- (WN) The untranslated word is the Greek definite article, which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those"). See this article for more.
over. -- (IW) There is nothing in the Greek that can be translated as "over" in the Greek source.
missing "brother" -- (MW) The untranslated word "brother" is the Greek noun which means "a son of the same mother," "a kinsman," or "a colleague." It was used more generally as an indication of friendship like we use "bro" today. -
missing "of yours" -- (MW) The untranslated word "thy" is the genitive form of the singular, second-person pronoun, which is most commonly the possessive form. This pronoun follows the noun so "of yours."
Ἐὰν (conj) "If" is ean, which is a conditional particle (derived from ei (if) and an (might), which makes reference to a time and experience in the future that introduces but does not determine an event.
δὲ (conj) "But" is de which means "but" and "on the other hand." It is the particle that joins sentences in an adversarial way but can also be an explanation of cause ("so").
ἁμαρτήσῃ [7 verses](verb 3rd sg aor subj act) "Trespass" is hamartano, which means "to miss the mark," "to fail in one's purpose," "to err," "to be mistaken," and "to neglect."
ὁ (article sg masc nom) Untranslated is the Greek definite article, hos, ("the").
ἀδελφός [37 verses](noun sg masc nom) "Brother" is adelphos, which means "son of the same mother," "kinsman," "colleague," "associate," and "brother."
σου, (pron 2nd sg gen) "Thy" is from sou which means "you" and "your." -- The word translated as "thy" is the possessive form of the second person pronoun.
ὕπαγε [47 verses](verb 2nd sg pres imperat act) "Go" is hypago, which means "to lead under," "to bring under," "to bring a person before judgment," "to lead on by degrees," "to take away from beneath," "to withdraw," "to go away," "to retire," "to draw off," and "off with you."
ἔλεγξον [4 verses](verb 2nd sg aor imperat act) "Tell him his fault" is elegcho, which "to disgrace," "to put to shame," "to cross-examine," "to question," "to test," "to prove," "to refute," "to put right," "to get the better of," "to expose," and "to decide a dispute."
αὐτὸν (adj sg masc acc) "Him" is from autos, which means "the same," and the reflexive pronouns, "myself," "yourself," "himself," "herself," "itself," or the oblique case of the pronouns, "him," "her," and "it." It also means "one's true self," that is, "the soul" as opposed to the body and "of one's own accord."
μεταξὺ [4 verses](adv)"Between" is metaxy, which means "in the midst" and therefore (of Place) "between," (of Time) "meanwhile," (of Qualities) "intermediate," and (of Degree) "the difference." As a preposition, it takes the genitive case and has the sense of "between" to parties to an agreement or discussion.
σοῦ (pron 2nd sg gen) "Thee" is from sou which means "you" and "your."
καὶ (conj/adv)"And" is from kai, which is the conjunction joining phrases and clauses, "and," or "also." After words implying sameness, "as" (the same opinion as you). Used in series, joins positive with negative "Not only...but also." Also used to give emphasis, "even," "also," and "just."
αὐτοῦ (adj sg masc gen) "Him" is from autos, which means "the same," and the reflexive pronouns, "myself," "yourself," "himself," "herself," "itself," or the oblique case of the pronouns, "him," "her," and "it." It also means "one's true self," that is, "the soul" as opposed to the body and "of one's own accord."
μόνου. [18 verses](adj sg neut gen) "Only" is monos, which means "alone,""solitary," "only," "single," "unique," "made in one piece," "without [someone]," "only [something]," "unique," "one above all others," and "on one condition only."
ἐάν (conj) "If" is from ean, which is a conditional particle (derived from ei (if)and an (might)) which makes reference to a time and experience in the future that introduces but does not determine an event.
σου (adj sg masc gen) "Thee" is from sou which means "you" and "your." -- The word translated as "thy" is the possessive form of the second person pronoun.
ἀκούσῃ, [95 verses](verb 3rd sg aor subj act) "Shall hear" is akouo, which means "hear of," "hear tell of," "what one actually hears," "know by hearsay," "listen to," "give ear to," "hear and understand," and "understand." The accusative object is the person/thing heard about, while the genitive is the person/thing heard from.
ἐκέρδησας [8 verses](verb 2nd sg aor ind act) "Thou hast gained" is kerdainô, which means "to gain," "to gain an advantage," "to derive profit from," and "to save yourself from."
τὸν (article sg masc acc) Untranslated is the Greek definite article, hos, ("the").
ἀδελφόν [37 verses](noun sg masc acc) "Brother" is from adelphos, which means "son of the same mother," "kinsman," "colleague," "associate," and "brother."
σου: (pron 2nd sg gen) "Thy" is from sou which means "you" and "your." -- The word translated as "thy" is the possessive form of the second person pronoun.
There is a sense here that if someone makes a mistake, it is to your benefit at least partly because you get to criticism him.