But evil men are all to be cast aside like thorns, which are not gathered with the hand. Whoever touches thorns uses a tool of iron or the shaft of a spear; they are burned up where they lie.
2 Samuel 23:6-7, NIV
These verses are a prelude to the action of David's three mighty men. They are not a guide to gardening practices, but instructions concerning combat. You might say, "Don't go into battle unarmed. Do not use your bare hands when fighting evil men."
A pastor could make much of this idea. "Be armed with the Word of God when you fight Satan" might be one. And this would be a good sermon I am sure. But since everything in the Bible means something other than what it says (to many), and I feel the non-literalists have these kinds of interpretations pretty well covered, I will take a literal stand.
We live in an era when we kill innocent people all the time. Police do it, the military does it, and the alphabet agencies do it. At the same time, we are told that "Violence is not the answer." I see a whole lot of cognative dissonance goin' on! "We can use violence, but you cannot."
So how do we handle thorn people? Not with bare hands, but with implements of iron. Today we use steel.