In the name of Allah, Most Gracious, Most Merciful.
Here is a saying of Imam Ali (May Allah be pleased with him):
Your talk (words) are your prisoner as long as you have not spoken. But, as soon as you speak, you become its prisoner.
Hoard your tongue as you hoard your gold and silver because it may be that one single word may take away your happiness and attract to you a calamity.