Psalms 50:18-20 - Joseph Benson’s Commentary on the Old and New Testaments

When thou sawest a thief Instead of reproving him, and witnessing against him, as those should do that declare God's statutes, or that profess his religion; thou consentedst with him Didst approve of his practices, and desire to share in the profits of his iniquitous proceedings. Or, thou didst run with, him, as תרצ עמו, tiretz gnimmo, may be rendered. Thou didst readily and eagerly associate thyself with him in his unrighteous actions. Thou didst yield to his motions, and that with great complacency and earnestness. And hast been partaker with adulterers By joining with them in their lewd and filthy practices. “In this and the two following verses,” says Dr. Dodd, “are represented the notorious vices of the synagogue, (the Jewish Church,) which was extremely corrupt in the time of Christ.” Thou givest thy mouth to evil To sinful or mischievous speeches. Thou hast an unbridled tongue, and castest off all restraints of God's law, and of thy own conscience, and givest thy tongue liberty to speak what thou pleasest, though it be very offensive and dishonourable to God, and injurious to thy neighbour, or to thy own soul. And thy tongue frameth deceit Uttereth lies or fair words, wherewith to deceive and circumvent those who deal with thee. Thou sittest and speakest against thy brother Thou sittest in the seat of the scornful to deride and backbite others, even those whom thou oughtest to respect and show kindness to, thy own relations, thy very brother: and this, not through inadvertency, or upon some sudden and great provocation, but it is thy constant and deliberate practice. This, the word תשׁב, teesheb, thou sittest, or continuest, implies. And thou art not only guilty of backbiting, or speaking evil of them when they are absent, and making known to others the follies or faults with which they are justly chargeable; but thou accusest them of things of which they are innocent. Thou slanderest even thine own mother's son And takest away his good name, which is better than all riches, yea, than life itself: and this in opposition to any express and often repeated commands.