What exactly did Rahab believe about the God of Israel?
Rahab believed the God of Israel is God in heaven above and in earth below, the God of creation, and the God she would serve. Her faith rested in who God was, not in full knowledge of Christ's death, burial, and resurrection.
Les explains that Rahab’s confession was, “the Lord your God, He is God in heaven above, and in earth below.” Her heart melted with the others in Jericho when they heard how Israel came out of Egypt and defeated the two Amorite kings beyond Jordan. Yet God was looking at the heart of this Gentile prostitute, and what He found was that she believed who God was. Les points out that faith did not always require recognition of Christ’s death, burial, and resurrection; even Abraham, when he left Ur of the Chaldees by faith, did not know all that much—only who God was and that He had told him to do something, and he obeyed by faith. In the same way, Rahab’s faith was in the fact that the God of Israel was the God of creation and the God she was going to serve. She then made a deal with Joshua’s spies to remember her family when the city was taken. Those family members who had faith enough to trust the spies’ promise were saved, not only from the Israeli invasion but spiritually.