Why did God command Killing in the Bible?

One of the most common objections raised against Christianity concerns the apparent contrast between the God of the Old Testament and the God revealed in the New Testament. Critics often portray the Old Testament God as harsh, wrathful, and judgmental, while seeing Jesus as loving, compassionate, and merciful.

In this interview, mathematician, philosopher, and Christian apologist John Lennox addresses this challenging question: Has God changed His mind about justice?

https://www.youtube.com/watch?v=tUjx10pX_4g