Deuteronomy 20:16-18 commands the Israelites to completely exterminate Canaanites living in the Promised Land. Israel is to leave nothing alive so that the Canaanites will not teach Israel to sin. All of this is very confusing to an average reader of Deuteronomy. It sounds like God is commanding genocide. So how can this text tell us anything about God’s grace?
In Joshua 10:26, Joshua implements this extermination, and after the defeat of the Canaanite kings, Joshua hangs them on trees until evening and then buries them in a cave sealed by stones. Joshua does this because of Deuteronomy 21:22. This passage says that if anyone commits a sin worthy of death, that person should hang dead on a tree cursed by God until evening when his body is taken down and buried.
Now, the word Jesus and the word Joshua are exactly the same in Greek. Jesus (Iesous in Greek) occurs 278 times in the Old Testament, and every single time it translates the word Joshua. Thus, in Jesus’ day when people spoke the name Jesus, they were saying the word “Iesous,” Joshua. In fact, three times in modern translations “Iesous” even is translated Joshua (see Luke 3:29; Acts 7:45 and Hebrews 4:8).
So when God instructs Joseph, “You will call his name Jesus, for he will save his people from their sins” (Matthew 1:21), God means for everyone to understand that Jesus is the new and merciful Joshua. The enemies are not Canaanites but each person’s own fallen sin nature.
Notice the contrast between Jesus and Joshua. The first Joshua rigorously carries out the command, but Jesus as the new Joshua so identifies with his people that he takes the guilt of their sin to himself. In Galatians 3:13, Paul even says, “Cursed is everyone who hangs on a tree.” Jesus hangs cursed on the cross for his people. He is placed into a cave, and a huge stone covers its mouth. Unlike the Canaanite kings, Jesus is not in that tomb today.
In the crucifixion, Jesus receives all of God’s wrath against sin. He takes to himself the “old man” (Ephesians 4:22; Galatians 2:19). He does this so that the curse of Canaan would fall on himself instead of his people. He is killing the Canaanite of the sin nature. In this way, Jesus purchases the new covenant so that the guilty would be transformed into the holy, merciful and righteous people of God. God means the brutality of the Canaanite purge to foreshadow what Jesus would endure for his people. In Matthew 15:22-28, Jesus offers grace even to a Canaanite woman. That grace saves all his people including each of us.