18 And all things whatsoever he does shall prosper. Never again shall His gift and His statutes be set at naught, as they were in the case of Adam, who by his sin in breaking the Law lost the happiness of an assured immortality; but now, thanks to the redemption wrought by the tree of Life, that is, by the Passion of the Lord, all that happens to us is eternal and eternally conscious of happiness in virtue of our future likeness to that tree of Life. For all their doings shall prosper, being wrought no longer amid shift and change nor in human weakness, for corruption will be swallowed up in incorruption, weakness in endless life, the form of earthly flesh in the form of God. This tree, then, planted and yielding its fruit in its own season, shall that happy man resemble, himself being planted in the Garden, that what God has planted may abide, never to be rooted up, in the Garden where all things done by God shall be guided to a prosperous issue, apart from the decay that belongs to human weakness and to time, and has to be uprooted.
Source: Homilies on the Psalms (New Advent)