15 Then she let them down by a cord through the window; for her house was on the side of the wall, and she lived on the wall. 16 She said to them, “Go to the mountain, lest the pursuers find you; and hide yourselves there three days, until the pursuers have returned. Afterward, you may go your way.” 17 The men said to her, “We will be guiltless of this your oath which you have made us to swear. 18 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. You shall gather to yourself into the house your father, your mother, your brothers, and all your father’s household.
Matthew Henry's Commentary on Joshua 2:15-18
Commentary on Joshua 2:8-21
(Read Joshua 2:8-21)
Rahab had heard of the miracles the Lord wrought for Israel. She believed that his promises would certainly be fulfilled, and his threatenings take effect; and that there was no way of escape but by submitting to him, and joining with his people. The conduct of Rahab proved that she had the real principle of Divine faith. Observe the promises the spies made to her. The goodness of God is often expressed by his kindness and truth, Psalm 117:2; in both these we must be followers of him. Those who will be conscientious in keeping promises, are cautious in making them. The spies make needful conditions. The scarlet cord, like the blood upon the doorpost at the passover, recalls to remembrance the sinner's security under the atoning blood of Christ; and that we are to flee thereto for refuge from the wrath of a justly offended God. The same cord Rahab used for the saving of these Israelites, was to be used for her own safety. What we serve and honour God with, we may expect he will bless, and make useful to us.