5 The first labour is, that you should be displeasing to yourself, that sins you should battle out, that you should be changed into something better: the second labour, in return for your having been changed, is to bear the tribulations and temptations of this world, and amid them to hold on even unto the end. Of these things therefore when he was speaking, while pointing out such things, he adds what? “You have shown to Your people hard things”: to Your people now, made tributary after the victory of David. “You have shown to Your people hard things.” Wherein? In persecutions which the Church of Christ has endured, when so much blood of martyrs was spilled. “You have given us to drink of the wine of goading.” “Of goading” is what? Not of killing. For it was not a killing that destroys, but a medicine that smarts. “You have given us to drink of the wine of goading.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)