17 “He will perform the will of them that fear Him”. He will perform it, He will perform it: though He perform it not at once, yet He will perform it. Certainly if therefore you fear God, that you may do His will, behold even He in a manner ministers to you; He does your will. “And He shall hear their prayer, and save them.” You see that for this purpose the Physician hears, that He may save. When? Hear the Apostle telling you. For we are saved in hope: but hope which is seen is not hope: but if what we see not we hope for, then do we with patience wait for it: “the salvation,” that is, which Peter calls “ready to be revealed in the last time.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)