'Linen' in the Bible

And Samson said, Now I have a hard question for you: if you are able to give me the answer before the seven days of the feast are over, I will give you thirty linen robes and thirty changes of clothing;

But if you are not able to give me the answer, then you will have to give me thirty linen robes and thirty changes of clothing. And they said to him, Put your hard question and let us see what it is.