“How would you differentiate between God’s instruction to Israel to purge Canaan of the various people groups located there and radical Islam’s jihad to purge the world of infidels?”
Many a Christian has wondered about God’s instructions to Israel to exterminate whole peoples in Canaan (Deut. 20:16,17), but there were reasons for this genocide, reasons that do not exist today.
When fallen angels took wives from among the daughters of men, they produced a race of giants in the early earth (Gen. 6:1-4). The purpose of the Flood was to exterminate that demonic race, Noah’s family being spared because he was “perfect in his generations” (6:9), i.e., not infected with this cursed seed.
Genesis 6:4 then describes another outbreak of giants that appeared “after” the days of the Flood, as Satan tried again to pollute the seed of the woman, frustrate the promise of Genesis 3:15, and prevent the birth of the Messiah. But since God had promised He would never again destroy the world with a flood (Gen. 9:11), it was left to the sword of Israel to wipe out this second eruption of giants, including Goliath, Og (Deut. 3:11) and many others (Num. 13:32,33; 2 Sam. 21:16-22).
This explains the seemingly heartless instruction to Joshua to exterminate the squatter nations that were sent there by Satan to contest the claim of Abraham’s seed to the land including, “all that breathed” (Josh. 10:40), “young and old” (Josh. 6:21), even their “little ones” (Deut. 2:34). But no such conditions exist on earth today, so any program that calls for the deaths of “unbelievers” is foreign to the Word of God rightly divided.
The story is told of a king who vowed to destroy his enemies, then proceeded to invite them all to a lavish feast. After the banquet, the king’s aides asked him what had become of his oath. “I did destroy my enemies,” he replied. “I destroyed my enemies by making them my friends!” Likewise, God’s only authorized method of destroying unbelievers today is by making them believers! source