The LORD your God himself will cross over ahead of you. He will destroy these nations before you, and you will take possession of their land. Joshua also will cross over ahead of you, as the LORD said. And the LORD will do to them what he did to Sihon and Og, the kings of the Amorites, whom he destroyed along with their land.
Deuteronomy 31:3-4 NIV
These words are a part of Moses’ final speech to Israel before he died. And he assured them that God would continue to go before them, giving them success as they conquered the land and made it their home. They would defeat the nations on the west side of the Jordan River just as they had defeated Sihon and Og, the kings who ruled east of the Jordan.
Moses told Israel that God had destroyed Sihon and Og. And that he would also destroy the nations who occupied the land promised to them. Yet, in the battles on both sides of the river, Joshua and the army of Israel fought and defeated these other nations.
So, did God destroy these nations? Or did Joshua and Israel’s army destroy them? The answer to both questions is yes. In the same way I might use a saw to cut a board, God used Israel to execute his judgment on those nations. The saw did the actual cutting, but I was the driving force behind the saw. And it was the army of Israel that did the actual fighting, but it was the Lord who empowered them and gave them success.
What was true of God using Israel in these battles is just as true today. As we submit to God, he uses us to carry out his work here in this world. For example, while I might have typed out what you are reading now, my prayer is always that God will give me the words to write. That he would do his work through me. Because if it is my work alone, it will have little real value.