4 “Then He shall speak unto them in His wrath, and vex them in His sore displeasure”. For showing more clearly how He will “speak unto them,” he added, He will “vex them;” so that “in His wrath,” is, “in His sore displeasure.” But by the “wrath and sore displeasure” of the Lord God must not be understood any mental perturbation; but the might whereby He most justly avenges, by the subjection of all creation to His service. For that is to be observed and remembered which is written in the Wisdom of Solomon, “But You, Lord of power, judgest with tranquillity, and with great favour orders us.” The “wrath” of God then is an emotion which is produced in the soul which knows the law of God, when it sees this same law transgressed by the sinner. For by this emotion of righteous souls many things are avenged. Although the “wrath” of God can be well understood of that darkening of the mind, which overtakes those who transgress the law of God.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)