2 Tim 2:16, NIV: "godless chatter." The Message: "pious talk that is only talk." Looks like two sides of the same coin, doesn't it? On the one hand, "godless chatter" sounds like things we say that we really shouldn't say - mean things, ugly things. And on the other hand, "pious talk that is only talk" sounds like somebody trying to appear religious, or to appear really together spiritually. Both are bad, and the advice in the verse is good: don't do it. Those who do just get more and more ungodly, or further and further from reflecting Jesus.
What comes out of your mouth is really important. Jesus talked about it in Mt 15:10-11 (TM). Some pharisees and teachers of the law had come to him with a complaint that his disciples were not washing their hands as the dietary traditions demanded. Jesus skewers them on their own inconsistencies, and then he delivers the real teaching. "What goes into your mouth isn't what makes you dirty. What comes out of your mouth is the thing that makes you dirty."
Peter asks for a further explanation a little later, and in verses 17-20 (TM), Jesus tells him that food goes into the body and then out of the body, but what comes out of our mouth comes from the heart. Mt 12:33-35 (TM) says that out of the overflow of the heart, the mouth speaks. Meaning that, when you're bumped hard enough, what comes out of your mouth will be evidence of what is in your heart.
James talks about this, too. In 1:26 (TM), he says that not keeping your tongue in control means your religion is not operating the way it should. In 3:3-5 (TM), James gives a couple of examples.
We put a bit in the mouth of a horse, and by that we guide it around. The idea is putting control over our own mouth, and that affects our entire person. Are you an angry person? Control your mouth, and that can begin to change. Are you a negative person? Control your mouth, say things that are more positive, and you will become a more positive person.
The second example is a big ship with a little rudder. I mean, all rudders are little, compared to the ship, but even so, the little rudder steers the big boat around. The idea here is very similar to what we talked about with the horse. The mouth is our control point. Exert control there, and you will begin to have more control over your entire life.