The following material is based on the books:
1. Carl B. Gibbs Principles of Biblical Interpretation
2. Henry A. Virkler Hermeneutics: Principles and Process of Biblical Interpretation
3. Understanding the Bible (published by ICI)
The differences between types and symbols:
1. A type always implies something in the future. A symbol is not determined by time.
2. A type always something actual - a person, a place, an event, or a commandment. A symbol can be invented.
3. A type may include several symbols.
4. A type is always concrete. A symbol is abstract.
5. A type always has some similarity with the antitype. A symbol may not have a similarity with the thing it represents.
Principles of interpretation of symbols:
1. Usually, there is only one comparison. Context should serve a measure of the only possible meaning of the symbol.
2. Try to find the explanation of the meaning of the symbol in the context. The Bible is the only interpreter of its symbols. If the author uses a symbol, it is implied that he will explain its meaning in the nearest context or that you know its meaning already from other texts.
3. There are no universal symbols in the Bible. The same word can be used as different symbols and in its literal meaning. It depends on the context.
4. If the author does not imply a symbol, then, there is no symbol there.