The creatures of this sensible world signify the invisible things of God [Rom., 1, 20], partly because God is of all creation the origin, exemplar, and end, and because every effect is the sign of its cause, the exemplification of the exemplar, and the way to the end to which it leads; partly from its proper representation; partly from prophetic prefiguration; partly from angelic operation; partly from further ordination. For every creature is by nature a sort of picture and likeness of that eternal wisdom, but especially that which in the book of Scripture is elevated by the spirit of prophecy to the prefiguration of spiritual things. But more does the eternal wisdom appear in those creatures in whose likeness God wished to appear in angelic ministry. And most specially does it appear in those which He wished to institute for the purpose of signifying which are not only signs according to their common name but also Sacraments.
[Bonaventure, The Mind's Road to God (Chapter 1, Section 12).]
