As Christians, our lives can be compared to a garden. We are responsible for taking care of what grows there. We need to constantly prune our gardens to remove unwanted things, like anger, pride, selfishness, etc, much like a gardener prunes his garden of weeds and unwanted plants.
Last year we had an overgrown area of poison ivy removed. It was a huge undertaking and required the help of several workers, lasting all day. I have since noticed the ivy slowly growing back. It would take years to get to the level it was, but still we need to stay on top of this and remove all the unwanted plants because just one can cause an allergic reaction.
In the same way, if we let unwanted emotions or words take root in our lives, we will have a harder time removing them. Stop these bad behaviors as soon as they show up. Take God's word and apply it to your circumstances. Planting His word into our hearts will result in His word coming out of our mouths when we need it. God says that His word is alive. He spoke all things into existence. We can either speak negative or positive words over our lives and the results will follow.