In the Church, symbolism plays a very important role for the Church is material and spiritual. The material can seen, and it is accessible, but the spiritual is indicated through symbols.
In the Church
The symbolism of the Church cannot be successfully studied outside the Liturgy. Separated from the divine services, symbolism loses its meaning and becomes a series of sterile abstractions. Symbols die when they are falsely invented, or rationally explained.
Symbolism expresses indirectly, through images, that which cannot be expressed directly materially or verbally. Symbolism hides truths which it reflects from those who are not initiated and makes them understandable to those who know how to approach them.
Symbol not just sign
There is a necessary spiritual distinction between symbol and sign. A sign only portrays reality. A symbol always qualifies it in a certain way, bringing forth a superior reality. To understand a sign is to translate an indication. To understand a symbol is to participate in the presence. Symbols are not mere illustrations, not are they a substitute of reality. They have the power and competence of manifesting God to men, signs into the genuine union and knowledge of things eternal and divine.
Also the Church uses bread, wine, wheat, oil, water, flowers, and fruits because their very being and existence as expressions of God, as symbols of his presence and action in the world for man, his love, mercy, goodness, life and the very presence given to man in creation and salvation. In short symbols of truth.
Light is a universal symbol for the mystical presence of God as the True, the Beautiful and the Good.