Behold, when we come into the land, you shall bind this line of scarlet thread in the window which you did let us down by: and you shall gather to you into the house your father, and your mother, and your brothers, and all your father's household.
They said, When we take the city, you leave this scarlet rope out, and everyone who is within the house will be saved. If any of your family goes out into the streets, then they're taking their lives into their own hands, they'll be slain with the rest of the people. But in order that they might be spared and be saved, they've got to stay in the house ( Joshua 2:18-20 ).