Stephen Dempster on how Joshua portrays the Israelite invasion of Canaan as a new flood (HT: Joel Martin):
Not only the curse of Ham echoes in the judgment of the Canaanites, but also that of the flood. There is to be total destruction as the Israelites sweep over the land, as agents of God’s judgement on the sin of the Amorites (Gn 15.16). The Nephilim are in the land as they were in the days before the great deluge (Num 13.33; cf. Jos 11.21–22).
This reading recalls to my mind a related thought on Isaiah 11, which though probably unoriginal will perhaps set Joshua more explicitly in the sweep of redemptive history. As all the earth becomes the domain of New Testament Israel, it is flooded with the knowledge of the Lord as the waters cover the sea (cf. 1 Pt 3.18–22). This is the judgement, when the Virga Jesse smites the earth with the word of his mouth. No joke: the Christ means serious business, and the final result, as the people of the earth come to know God through him and are ruled by his divine Spirit in them, is a restored world in which the sucking child shall play on the hole of the asp, and the weaned child shall put his hand on the cockatrice’ den, the ancient enmity with serpents abolished because evil is wiped out. Of this perfect flood the Lord’s flooding of Canaan is a sign.