What does it mean to say the Lord is my refuge and my fortress?

First, let us define the meaning of refuge and fortress. They are similar but not the same. A refuge is a place people can run to in times of danger. For example, the city of refuge in the Bible is a place where people could run to and be safe. A fortress is a place designed for battle. In times of battles, a fortress is a walled city supplied with food, ammunition etc. God is our refuge and fortress, our help in times of danger. God's security for his people is eternal.