One of the enduring mysteries for those who read the Bible is how a God of love could condone the killing of foreign people in the Old Testament. The New Testament clearly advocates peace, so no-one can therefore legitimately promote violence in the name of Christianity. However, the Old Testament not only represents a different era and culture, but a different approach to life, despite the same God having authored it. It is unfair to judge a society of the past by the standards of the present in any era.
The genocide advocated back then was in the interests of purifying and protecting the people of God. The foreign nations had all ultimately derived from God but had then turned their backs on Him. God’s favour could only be earned by freedom from sin and the sin could only be atoned by the shedding of animal blood sacrifice. This was a prototype of the coming of Jesus whose blood would atone for sin once for all time and would therefore avoid the need for our purification in the same ways that the Old Testament people achieved it.
By killing their pagan neighbours, the Israelites were removing the temptation to idolatry and the heathen practices that were an offence to God who, since He created people, gets to set the rules about their behaviour. In the end, though, the overarching relevance for us is not only that God needs purity of life that cannot be achieved in our own strength, only through Christ, but also that the Old Testament symbolism has instructional value for how we live life today. More on that tomorrow!