“we have heard how Yahweh dried up the water of the Red Sea before you.” Rahab had heard of the Red Sea (the Hebrew reads “Reed Sea”) drying up before the Israelites, an event that had occurred 40 years earlier. Nearly every book of the Old Testament mentions the Exodus in one way or another, giving strong evidence that it was a historical event.
“devoted to destruction.” The Hebrew word translated “devoted” is cherem and means a thing that is “devoted.” It can be “devoted” to Yahweh in the sense of being set apart to Him and therefore being His and holy, or it can be a thing “devoted” to Him in the sense that it is an abomination to Him and thus it will be destroyed; in that case, “devoted to destruction” is the meaning. Generally, this specific phrase was used when the city and its inhabitants were destroyed, and the booty was taken, especially the metals, to the Tent of Meeting (Tabernacle). There is no record of Israel taking spoil or of dedicating it to Yawheh in the Sihon/Og battles, so they may or may not have. We only know from the text that Israel dispatched the people and possessed the land. It is likely that Rahab knew more than we do. The word has entered English as “harem” a group of women set apart for one man. [For more on “devoted,” see commentary on Josh. 6:17].