'Scarlet' in the Bible

Behold, when we come into the land, thou shalt bind in the window this line of scarlet thread by which thou hast let us down; and thou shalt gather to thee in the house thy father, and thy mother, and thy brethren, and all thy father's household;

And she said, According to your words, so be it. And she sent them away, and they departed. And she bound the scarlet line in the window.