Joshua said, Hereby you shall know that the living God is among you, and that he will without fail drive out from before you the Canaanite, and the Hittite, and the Hivite, and the Perizzite, and the Girgashite, and the Amorite, and the Jebusite.
Evidently the pushing back of the waters of the Jordan was to be a sign to the Israelites that God would push back the Canaanites (Joshua 3:10). The title "the Lord of all the earth" occurs here (Joshua 3:11) first in Scripture indicating Yahweh’s absolute sovereignty over this planet. Because He was "the Lord of all the earth" He could give Canaan to the Israelites.