Verse 20. - And if thou utter this our business. This was an obvious condition. Rahab's betrayal of the spies could not save Jericho, but it would destroy them, or at least expose them to imminent danger. She would, therefore, by mentioning the matter, deprive herself of all title to protection.

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, Ps 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.And if thou utter this our business,.... So that others would either hang out scarlet threads or get into her house for shelter; see Gill on Joshua 2:14,

then we will be quit of thine oath which thou hast made us to swear; be under no obligation to make it good, by saving her and her father's house.