Joshua 2:17 & 18
"Now the men had said to her, 'This oath you made us swear will not be binding on us unless, when we enter the land, you have tied this scarlet cord in the window through which you let us down, and unless you have brought your father and mother, your brothers and all your family into your house.'" NIV translation
There were two additional responsibilities that Rahab had in order for her and her family to be saved.
First, she had to tie a red cord to the window that she had let the spies out through. This was a marker for the men to identify the house when they came back into the city. It reminds us of the fact that there is only one way to be saved and that is through the blood of Jesus Christ.
The second thing that she had to do was to get all of her family into her house. This is an important fact in that many people think that, since their mom or dad have been a part of the church for years, they are as well. But, as we see it was not their relationship with Rahab that was going to save them, but their location (being in her house).