"Put on, then, garments that suit God's chosen and beloved people: compassion, kindness, humility, gentleness, patience." (Colossians 3:12 REB)
[We] call it gentleness, but the Greeks called it praotes. Aristotle said that praotes was the perfect mean between too little anger and too much anger.
[You] thought anger was always bad?
Not at all. No reform movement would ever have happened if someone hadn't gotten angry about the state of things as they found them. It was when people grew angry about slavery that its death knell was sounded. So, too, with child labor.
But the problem is to harness that anger. That's where praotes -- gentleness -- comes in. Anger destroys even in the name of great causes; without restraint, anger will defeat the very matters it endorses. And our usual brand of self-control won't make it. As William Barclay used to say, we need to be God-controlled. That’s gentleness. Because gentleness is power under purposeful direction.
-- J. Ellsworth Kalas in New Testament Stories from the Back Side