I. The contemplation of the prophecies of Christ's suffering are a great source of pious delight
The minds of the faithful, beloved, ought indeed always to be occupied with wonder at God's works and their reasoning faculties devoted particularly to those reflections by which they may gain increase of faith. For so long as the pious heart's attention is directed either to the benefits which all enjoy, or to special gifts of His grace, it keeps aloof from many vanities and retires from bodily cares into a spiritual seclusion. But this must be the more eagerly and thoroughly done at the season of the Lord Passion, that what is then read in the sacred lections may surely be received with the ears of understanding, and that the themes which are great in word may be seen to be yet greater from the mysterious realities which underlie them.
For the first reason for our lifting up our hearts is that the voices of the prophets have sung of the things which the truth of the Gospel has also narrated, not as destined to happen, but as having happened, and that what man's ears had not yet learned was to be accomplished, was already being proclaimed as fulfilled by the (Holy) Spirit. For King David, whose seed according to the flesh is Christ, completed his lifetime more than 1,100 years before the day of the Lord's Crucifixion, and endured none of those punishments which he relates as inflicted upon himself.
But because by his mouth One spoke Who was to take suffering flesh of his stock, the story of the cross is rightly anticipated in the person of him who was the bodily ancestor of the Saviour. For David truly suffered in Christ, because Jesus was truly crucified in the flesh which He had from David.
Source: Sermons (New Advent)