There is something so heavy on my heart that I feel like I could deliver a fairly lengthy, poorly delivered sermon on the topic.
They can give life, they can cause death.
Not just for the hearer/receiver of the words, but also for the speaker of the words.
Matthew 12:34 says, "Out of the heart, the mouth speaks."
We can learn a lot about the condition of our hearts just by looking at the things we are saying. A critical heart produces a critical tongue. A self-righteous heart produces a judgmental tongue. A loving heart produces a gracious tongue. A peaceful heart produces a reconciling tongue. There will always be things done to us that we don't agree with. But how we respond is only a reflection of our own heart. No one else's. And if it is true that God is only concerned with the state of our hearts, then the words we say aren't merely words, but rather one of the most tangible ways of knowing what God is seeing when he looks at our hearts.