If you are going to use the word of God as evidence then you must also consider in Romans when Paul wrote "For the wages of sin is death..."
If you believe, as I do, that all of us who have had the chance at some point in our lives have sinned then really we deserve nothing less. But yet out of God's grace and forgiveness He allowed for a sacrifice in our place.
Further I would argue that when God took the lives of people, or instructed Israel to, it was just and never without cause.
This. God has the right to take any of our lives whenever he pleases. Murder is defined as "unlawful killing with malice aforethought." Because sin (and our sin nature) legally condemns us to die in our physical bodies, we are all effectively on death row; when God chooses to carry out this penalty does not negate its legality. Furthermore, there is no malice in God; no darkness resides in him at all (1 John 1:5); however, even if you find the Biblical God to be malicious, you cannot call him murderous because he cannot kill any human unlawfully by definition.
So he is our prosecutor, judge, and jailer.... we were born to serve a life sentence. No wonder we cry when we come out.