11 “When His anger shall be shortly kindled, blessed are all they who put their trust in Him;” that is, when the vengeance shall come which is prepared for the ungodly and for sinners, not only will it not light on those “who put their trust in” the Lord, but it will even avail for the foundation and exaltation of a kingdom for them. For he said not, “When His anger shall be shortly kindled,” safe “are all they who put their trust in Him,” as though they should have this only thereby, to be exempt from punishment; but he said, “blessed;” in which there is the sum and accumulation of all good things. Now the meaning of “shortly” I suppose to be this, that it will be something sudden, while sinners will deem it far off and long to come.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)