Albert Barnes Commentary Job 19:29

"Be ye afraid of the sword: For wrath [bringeth] the punishments of the sword, That ye may know there is a judgment." — Job 19:29 (ASV)

Be you afraid of the sword - Of the sword of justice, of the wrath of God. In taking such views, and using such language, you ought to dread the vengeance of God, for he will punish the guilty.

For wrath brings the punishments of the sword - The word “bringeth” is supplied by the translators, and as it seems to me improperly. The idea is, that wrath or anger such as they had manifested, was proper for punishment; that such malice as they had shown was a crime that God would not suffer to escape unpunished. They had, therefore, everything to dread. Literally, it is, “for wrath the iniquities of the sword;” that is, wrath is a crime for the sword.

That you may know that there is a judgment - That there is justice; that God punishes injuries done to the character, and that he will come forth to vindicate his friends. Probably Job anticipated that when God should come forth to vindicate “him,” he would inflict exemplary punishment on “them;” and that this would be not only by words, but by some heavy judgment, such as he had himself experienced. The vindication of the just is commonly attended with the punishment of the unjust; the salvation of the friends of God is connected with the destruction of his foes. Job seems to have anticipated this in the case of himself and his friends; it will certainly occur in the great day when the affairs of this world shall be wound up in the decisions of the final judgment. See (Matthew 25:0).