Rahab said Jericho had heard how the LORD dried up the water of the Red Sea before Israel when they came out of Egypt Joshua 2:10. She also mentioned what Israel did to Sihon and Og, the Amorite kings east of the Jordan Joshua 2:10.
In Joshua 2:8–11, Rahab goes up to the roof and speaks to the two Israelite men before they sleep. She says she is certain Yahweh has already decided to give Israel the land. This scene sits inside the Jericho reconnaissance story (Joshua 2), where Joshua sends spies ahead of Israel’s entry into Canaan. Rahab has hidden the men and misdirected the city’s search, and now she interprets what the spies’ presence means for Jericho’s future.
Rahab’s speech explains Jericho’s fear in religious terms. She connects public reports of Yahweh’s earlier acts (the Red Sea and victories over Sihon and Og) to a collapse of morale in the region. In the text, fear is not just psychological; it is a response to what people believe Yahweh has already done and will do.
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with Joshua 2:10, then read the surrounding section so the answer stays connected to the passage's flow.
10For we have heard how Yahweh dried up the water of the Red Sea before you, when you came out of Egypt; and what you did to the two kings of the Amorites, who were beyond the Jordan, to Sihon and to Og, whom you utterly destroyed.