God's "words" created the universe--and each one of us. We are made in His image, so our words also have power. Because of our fallen nature, our words also have destructive power.

Whether or not you're a Christian, or even a theist, this advice from Paul to the church in Philippi is worth following, regardless of your world view:

"Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things."

What we think about most comes out of our mouths. Like it or not, that's how we're made.