Thank you for the question, “Was it really necessary for the Israelites to destroy all the people living in Canaan?”
There is a misconception that the Israelites destroyed all the Canaanites. The Israelites were commanded by the LORD God to destroy the inhabitants of the Promised Land but they failed to obey his command. The Israelites allowed the Canaanites to dwell in the land with them. One can read Judges 1:27–3:5 on the disobedience by the Israelites and God testing of them for their obedience to him.
Deuteronomy 7 states the reason why God commanded the Israelites to destroy all the Canaanites and their deities. “When the LORD your God brings you into the land you are entering to possess and drives out before you many nations—the Hittites, Girgashites, Amorites, Canaanites, Perizzites, Hivites and Jebusites, seven nations larger and stronger than you— 2 and when the LORD your God has delivered them over to you and you have defeated them, then you must destroy them totally. Make no treaty with them, and show them no mercy. 3 Do not intermarry with them. Do not give your daughters to their sons or take their daughters for your sons, 4 for they will turn your children away from following me to serve other gods, and the LORD’s anger will burn against you and will quickly destroy you. 5 This is what you are to do to them: Break down their altars, smash their sacred stones, cut down their Asherah poles and burn their idols in the fire. 6 For you are a people holy to the LORD your God. The LORD your God has chosen you out of all the peoples on the face of the earth to be his people, his treasured possession” (A searchable online Bible in over 150 versions and 50 languages).
The reasons why the total destruction of the Canaanites w (vere necessary are as follows:
A. The Canaanites will turn the Israelites devotion to the LORD God to worship their deities (vs. 4).
B. The Israelites are to be a holy, devoted people to the LORD God (vs. 6).
C. The Canaanites were to be destroyed for their wickedness (Gen. 15:16).
Deuteronomy 16 says this, “When you enter the land the LORD your God is giving you, do not learn to imitate the detestable ways of the nations there. 10 Let no one be found among you who sacrifices their son or daughter in the fire, who practices divination or sorcery, interprets omens, engages in witchcraft, 11 or casts spells, or who is a medium or spiritist or who consults the dead. 12 Anyone who does these things is detestable to the LORD; because of these same detestable practices the LORD your God will drive out those nations before you. 13 You must be blameless before the LORD your God” (NIV).
God gave the Canaanites four hundred more years to repent of their evil ways. In those four hundred years, they continued in their evil ways. The sacrifice of their children to Molech was most detestable to God.
Was it necessary that God commanded the Canaanites to be destroyed? As one reads the history from Judges through the Kings, the Israelites followed the ways of the Canaanites, even the Assyrians-Babylonians deities. King Manasseh did more evil than any of the previous kings in Israel so much that the LORD God also brought judgment on them for their sins. God didn’t excuse the sins of Israel. They suffered destruction of their homeland and death among the people.
One must remember that the Israel was living in a theocracy, not a republic or democracy. God was to be their King.
SUMMARY: God’s judgment is just even as he gave the Canaanites time to repent.
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