Rahab seems like an unlikely person to be named in the Hall of Faith. She was a foreigner and a prostitute (a dodgy job then and now!). When two Hebrew spies came into Jericho to check out the land, she saved their lives by hiding them and helping them escape.
She did this because she heard many stories of God and the miracles He performed. She believed that He was the One true God, and she made sure she was on God’s side. This took faith. The funny thing about faith is that God gives it to us as a gift, we just need to believe and take it.