Let’s see if this scenario fits your life: you are getting ready for church on Sunday, and the house is full of chaos – running, screaming, bad tempers, bad moods – and then we go to church and worship Jesus as our Prince of … Peace.
This doesn’t mean that getting ready it supposed to be easy – it is hard to get out the door, and we have hard feelings sometimes. Yet James here calls us to think about having a consistent MOUTH – a mouth that always is about peace, is not praising and kind in one minute and cursing and rude in the next. “Doesn’t it depend on how we are treated?” – no, my character can’t change depending on the actions of others – if Christ is alive in me, then I need to grow so that I am always a person of peace, even when the world is warring around me. That is hard change, hard growth; and that is why James says that no one has tamed the tongue.
http://nlt.scripturetext.com/james/3-3.htm