For we have heard how the LORD dried up the water of the Red sea for you, when ye came out of Egypt; and what ye did unto the two kings of the Amorites, that were on the other side Jordan, Sihon and Og, whom ye utterly destroyed.
We know about how God stopped the Red Sea's water for you when you left Egypt, and how you defeated the two Amorite kings, Sihon and Og, on the other side of the river Jordan, completely defeating them.