We tend to not remember what dispensation/time/season we are in. God handled sin with judgement, and the only thing keeping back His judgement today is the atonement. That's it. And there's coming a future day of Judgement (see John's description in The Revelation). We tend to see God through pastel, nursery-rhyme colors, but forget His true character. This is why the OT is so important to our faith today. We must know His ways.
There is no polarity (in principles ways) between the OT and NT. In Ezekiel God says, "The soul who sins is the one who will die." In Romans we find "the wages of sin is death." In Ezekiel, God says "I take no pleasure in the death of anyone." In 1 Peter, Paul writes "He is patient with you, not wanting anyone to perish." Both testaments proclaim the way to avoid "death": REPENT! (
Ezekiel 18:32, 2 Peter 3:9).
The elements of truth to us today, about how thorough God's judgements are, should be something we take note of. When we allow Him to purge us of ungodliness, we should "kill all" and not leave nothing undone. He doesn't want a half-job, he wants those who will leave all and follow Him.
God wants LIFE for us. We (sadly) often choose death.