no real military purpose. It is not to keep missiles from being targeted. What is its point?
Sacramental, pointing back to Passover.
And so we come to the scarlet thread. Joshua 2:18-19 records the instructions of the spies to Rahab in this way:
Behold, when we come into the land, you shall tie this scarlet cord in the window through which you let us down, and you shall gather into your house your father and mother, your brothers, and all your father's household. Then if anyone goes out of the doors of your house into the street, his blood shall be on his own head, and we shall be guiltless. But if a hand is laid on anyone who is with you in the house, his blood shall be on our head.
Why a scarlet cord? First things first: this cord probably belonged to Rahab and was not the rope by which the spies were let down. It is hard to conceive any reason ancient or modern for dying scarlet a rope thick and long enough to lower grown males through windows. It is even less conceivable, the Scarlet Pimpernel notwithstanding, that spies seeking to avoid attention would be carrying such a conspicuous rope on their mission. Scarlet is not the color of utilitarian ropes preferred by spies.
It is very conceivable, however, that a harlot would have some scarlet cord for decorative, fashionable purposes in her inn. Scarlet is a fashionable color associated with luxury, as in Proverbs 31:21. The spies saw the cord close at hand, recognized it would work perfectly as a signal, and instructed Rahab to use it.
That said, what was the significance of the scarlet cord? One of the more curious interpretations is that of Richard Gabriel (The Military History of Ancient Israel, p. 132). While the Israelites were marching around the city, drawing attention and raising great clouds of dust, the scarlet rope allowed small groups of soldiers to sneak into the city through Rahab's window. The resulting "collapse" of the defenses might not have been the miraculous tumbling of the walls recorded in Joshua 6, but it was just as effective. I have no idea how one could prove such a thesis. It is certainly not what the author of Joshua intended.
The actual words of the spies provide the interpretive key. Scarlet ... window ... household inside ... death outside ... blood. The story is begging us to think of Passover. The wrath of God falls on wicked humanity even as he saves his chosen people. In Egypt, Hebrew familes were saved by gathering for protection in homes marked by blood.
God has given the Canaanites four hundred years to bring their sin to "full measure" (Genesis 15:16). The time of wrath has come. Whereas Israel huddled in homes while God punished the Egyptians, here they will watch and participate. Salvation is offered to righteous Rahab because she has recognized the God of Israel and sided with his people Israel. She will be saved as Israel was, by huddling with her family in the midst of God's wrath in a home marked by scarlet. This has a utilitarian purpose - the soldiers of Israel will be instructed to save the family huddled in the home marked by the scarlet cord. But the cord holds the same religious significance as the blood of the lamb.
Christian tradition has seized on this religious connection between the scarlet cord and the blood of the lamb. The Passover lamb is a type of Christ, the one whose blood would cover us and save us from the wrath of God. Rahab's scarlet cord signifies the same truth, that Christ's blood alone offers protection. Her repentant obedience brought Rahab's family into the people of God. Her marriage into the royal line, as we will examine in tomorrow's study, shows the completeness of her conversion and the fullness of God's cleansing grace.
She entered symbolically under the blood.
And as the blood of the passover saved those who were in Egypt, so also the blood of Christ will deliver from death those who have believed. Would God, then, have been deceived if this sign had not been above the doors? I do not say that; but I affirm that He announced beforehand the future salvation for the human race through the blood of Christ. For the sign of the scarlet thread, which the spies, sent to Jericho by Joshua, son of Nave (Nun), gave to Rahab the harlot, telling her to bind it to the window through which she let them down to escape from their enemies, also manifested the symbol of the blood of Christ, by which those who were at one time harlots and unrighteous persons out of all nations are saved, receiving remission of sins, and continuing no longer in sin.
Justin Martyr, Dialogue with Trypho, ch. 111 (mid-2nd century, AD)