As soon as we had heard it, our hearts did melt, neither did there remain any more spirit in any man, because of you: for Yahweh your God, he is God in heaven above, and on earth beneath.
The two spies did attach one condition to their promise, that being, that under no circumstance would the woman betray their mission  (Joshua 2:14).  Also, there was the agreement that the identity of Rahab's house would be indicated by the red cord.