There are such wonderful explanations of symbolism posted. I wonder if I can really add to them.
The entire bible is a book explaining God to us, who understands and works in a way that is different than our understanding and ways. We are human in flesh. God is in spirit. So God uses what we know of our world to explain the part of our world it is harder for us to understand. Other posters have given you examples of this.
Our whole world is a reflection of God. The stars show the order, and there are mystical symbols there that we don't understand. What we do, day to day, even is a reflection or symbol. For thousands of years, for instance, before Christ came, God set up a system of blood sacrifice for atonement. This was a symbol of Christ, although the people using the blood for sacrifice had no idea what it was all about. We have known for these 2,000 years, because we are know about Christ.
You will probably never understand all the symbols that God uses to explain the spiritual to us, but it will tell you how obedience to what God says often has a deeper meaning spiritually than we understand.