The spies told Rahab to tie a scarlet cord in the window through which she let them down Joshua 2:18. It marked the house where Rahab and her family were to gather so they would be spared when Israel took the city Joshua 2:18–21.
In Joshua 2:17–21, the two scouts clarify the conditions under which they will be free from responsibility regarding Rahab’s oath. They give Rahab a visible sign to mark her house: a scarlet cord in the window where she lowered them. They also require that her family stay inside that house; anyone who leaves loses the protection promised. This unit sits inside the Jericho spy episode (Joshua 2), where Israel’s entry into the land begins with intelligence-gathering rather than open battle. Rahab has hidden the scouts and helped them escape, and she has asked for kindness toward her household in return for her help.
These verses read like the stated terms of a high-stakes promise made in a crisis. The scouts do not cancel what they swore to Rahab; they define when they will be “guiltless” (free from responsibility) regarding that oath.
A common mistake is to turn the wording into a slogan. The better reading keeps the phrase tied to the passage, the speaker, and the problem the book is addressing.
Start with Joshua 2:18, then read the surrounding section so the answer stays connected to the passage's flow.
18Behold, 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.