Dyed in the wool

The expression "dyed in the wool" refers to a state of steadfastness, usually in one's political, religious or social beliefs. The expression comes from the fact that fabric can be dyed in a number of ways. The woven fabric may be dyed after it is complete, or the threads may be dyed before they are woven. When a color is "dyed in the wool," the wool itself is dyed before being spun into threads, so the color is least likely to fade or change.