1 Thessalonians 4:6

that noman go beyond and defraud his brother in any matter More exactly, that none overreach and take advantage of his brother in the matter. "The matter" is obviously that which occupies the last two verses. Acts of Impurity are socialwrongs, as well as sins against the offender's person. The warning may include any injury done to another touching the affections and engagements that belong to marriage, "the matter" concerned in the present charge which is expressly violated by "fornication." The Apostle sets the wrong in the strongest light: it is to "cheat one's brother," and that in what touches most nearly the sanctities of life. Hence the stern warning that follows:

because that the Lord is the avenger of all such Rather, an avenger; and concerning all these things in everything that concerns the honour of the human person and the sacredness of wedded life. Comp. Hebrews 13:4, "Let marriage be had in honour … Fornicators and adulterers God will judge." It is written that "Vengeance belongs to God;" and in this matter He is peculiarly bound to exercise it.

as we also have forewarned you and testified or, solemnly attested: the latter verb implies reference to God, as it is expressed in 2 Timothy 4:1, "before God and Christ Jesus." On this subject it appears as to the moral consequences of faith in Christ and the social purity that belongs to the sanctified life the apostles at Thessalonica had spoken very plainly and solemnly from the first.