2 There is another interpretation concerning the wine-presses, yet still keeping to the meaning of Churches. For even the Divine Word may be understood by the grape: for the Lord even has been called a Cluster of grapes; which they that were sent before by the people of Israel brought from the land of promise hanging on a staff, crucified as it were. Accordingly, when the Divine Word makes use of, by the necessity of declaring Himself, the sound of the voice, whereby to convey Himself to the ears of the hearers; in the same sound of the voice, as it were in husks, knowledge, like the wine, is enclosed: and so this grape comes into the ears, as into the pressing machines of the wine-pressers. For there the separation is made, that the sound may reach as far as the ear; but knowledge be received in the memory of those that hear, as it were in a sort of vat; whence it passes into discipline of the conversation and habit of mind, as from the vat into the cellar: where if it do not through negligence grow sour, it will acquire soundness by age. For it grew sour among the Jews, and this sour vinegar they gave the Lord to drink. For that wine, which from the produce of the vine of the New Testament the Lord is to drink with His saints in the kingdom of His Father, must needs be most sweet and most sound.
3. “Wine-presses” are also usually taken for martyrdoms, as if when they who have confessed the name of Christ have been trodden down by the blows of persecution, their mortal remains as husks remained on earth, but their souls flowed forth into the rest of a heavenly habitation. Nor yet by this interpretation do we depart from the fruitfulness of the Churches. It is sung then, “for the wine-presses,” for the Church's establishment; when our Lord after His resurrection ascended into heaven. For then He sent the Holy Ghost: by whom the disciples being fulfilled preached with confidence the Word of God, that Churches might be collected.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)