A lot of people think it’s death penalty “versus” God’s mercy. Truth is, the death penalty is God’s mercy.
Consider Joshua and Achan [Joshua 7]. Israel’s battle against Jericho was a piece of cake. They demolished its fortified wall and strong people without a sweat. But Achan saw gold and silver coins among the set-apart things from Jericho and stole them.
So, when they fought the next enemy stronghold called Ai—which was a lot smaller than Jericho—they were badly defeated. It was all because of Achan’s sin. Until this sin was dealt with, God declared that, “For now Israel itself has been set apart for destruction.”
In other words, Israel faced the “death penalty” as a nation from God.
To resolve this, God told Joshua what to do with the guilty person: “The one who has stolen…will himself be burned with fire, along with everything he has, for he has broken the covenant of the Lord and has done a horrible thing in Israel.”
In other words, death penalty. God himself told Joshua to sentence the crook with the death penalty.
So that Israel would be saved from being set apart for destruction. That was God’s mercy on Israel. For God to spare Israel and have mercy on them, Achan and his family must suffer death.
Then Joshua and all the Israelites took Achan, the silver, the robe, the bar of gold, his sons, daughters, cattle, donkeys, sheep, goats, tent, and everything he had, and they brought them to the valley of Achor. Then Joshua said to Achan, “Why have you brought trouble on us? The Lord will now bring trouble on you.” And all the Israelites stoned Achan and his family and burned their bodies.
Likewise, today, instead of all of us suffering in the hands of hardened criminals whose hobby is commit heinous crimes, we can apply the death penalty if it becomes part of the law of the land.
The New Testament endorses death penalty.
For the one in authority is God’s servant for your good. But if you do wrong, be afraid, for rulers do not bear the sword for no reason. They are God’s servants, agents of wrath to bring punishment on the wrongdoer. [Romans 13.4]
The term “sword” connotes the death penalty, not life imprisonment.
But some would say that Jesus never espoused death penalty but love and forgiveness and mercy. Well, fact is, the whole bible is the Word of God—because Jesus Christ is the Word of God [Revelation 19.13]. Even if he didn’t mention it in the Gospel, he supported it by the mere fact that it is in the letter to the Romans in the New Testament.
And God’s judgment is his love and mercy.
Jesus will never contradict God’s Word in the bible.
As simple as that.