Bodily manifestations so reveal the mysteries of heaven
that, although matter by itself cannot convey the full spiritual
meaning, yet to regard them only in their material aspect is to
mutilate them. We should have expected to hear that there were
trees, not one tree, standing on either side of the river shewn to the
saint. But because the tree of Life in the sacrament of Baptism
is in every case one, supplying to those that come to it on every side
the fruits of the apostolic message, so there stands on either side of
the river one tree of Life. There is one Lamb seen amid the
throne of God, and one river, and one tree of Life: three figures
wherein are comprised the mysteries of the Incarnation, Baptism and
Passion, whose leaves, that is to say, the words of the Gospel, bring
healing to the nations through the teaching of a message that cannot
fall to the ground.