Joshua 2:12
Now therefore, I pray you, swear unto me by the LORD, since I have shewed you kindness, that ye will also shew kindness unto my father’s house, and give me a true token: Now therefore, I pray you, swear unto me by the LORD, since I have shewed you kindness, that ye will also shew kindness unto my father’s house, and give me a true token:
The request belongs to the story of Rahab, a Canaanite who turned away from idolatry to worship the true God and joined His chosen people.
Her plea for safety for her father's house shows the divine purpose that people from other nations who turned to God were to be united with His chosen people.
Through Israel's sacrificial service Christ was to be lifted up and made known, so that all who looked to Him in faith could live.