29 “Therefore was the wrath of the Lord kindled against His own people”. Our translators have been unwilling to use the word anger, for the Greek θυμὸς; though some have used it; while others translate by “indignation” or “mind.” Whichever of these terms be adopted, passion does not affect God; but the power of punishing has assumed this name metaphorically from custom.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)