Sometimes we know that saying something will make a situation worse. We can tell ourselves to, "Just keep silent." If we feel tempted to speak negatively about someone, we can strengthen our resolve not to say it by telling ourselves, "Just keep silent."
The more difficult it is to keep silent, the greater the resulting spiritual elevation. When you tell yourself, "Just keep silent," your silence isn't just a passive state of being. Rather, it is an act of remaining silent.
In Tehillim (Psalms 34), King David tells us: "Who is the person who wants life and loves days that he may see good? Guard your tongue from evil and your lips from speaking deceit." Remaining silent instead of speaking against others enhances and lengthens life.
(from Rabbi Zelig Pliskin's book: "Conversations With Yourself", p.145) [Artscroll.com])