How was Israel supposed to take over the land of Canaan if God was going to drive the Canaanites out?

Les explains that God had a system to remove the Canaanite population while leaving everything intact. He compares it to a bomb that kills people but leaves things intact, perhaps a neutron bomb as Les speculates. Israel's only task was to walk in and take over with God's blessings. God's first instruction was simply, "Go in and take it," not to send spies. Their request for twelve spies came from unbelief; God condescended, but it was not His original intent. Les notes that if the spies had returned with faith and they had gone in, God would have let them take the land. The failure was unbelief, which Les calls awful, and he ties it to why people end in the lake of fire: not primarily works but unbelief as the cause.