4. Behold--calling attention to their coming doom as no vain threat.
      labourers--literally "workmen."
      of you kept back--So English Version rightly. Not as ALFORD, "crieth out from you." The "keeping back of the hire" was, on the part OF the rich, virtually an act of "fraud," because the poor laborers were not immediately paid. The phrase is therefore not, "kept back by you," but "of you"; the latter implying virtual, rather than overt, fraud. James refers to De 24:14, 15, "At this day . . . give his hire, neither shall the sun go down upon it, lest he CRY against thee unto the Lord, and it be sin unto thee." Many sins "cry" to heaven for vengeance which men tacitly take no account of, as unchastity and injustice [BENGEL]. Sins peculiarly offensive to God are said to "cry" to Him. The rich ought to have given freely to the poor; their not doing so was sin. A still greater sin was their not paying their debts. Their greatest sin was not paying them to the poor, whose wages is their all.
      cries of them--a double cry; both that of the hire abstractly, and that of the laborers hired.
      the Lord of sabaoth--here only in the New Testament. In Ro 9:29 it is a quotation. It is suited to the Jewish tone of the Epistle. It reminds the rich who think the poor have no protector, that the Lord of the whole hosts in heaven and earth is the guardian and avenger of the latter. He is identical with the "coming Lord" Jesus (Jas 5:7).

JFB.