Hold Back the Tongue
Writing to his family as he set out for Eretz Yisroel, the Gaon names the lifelong task of every person: to restrain the mouth and the appetites.
In the letter he wrote to his family on the road to Eretz Yisroel, the Gaon explains what a person's work in this world really is. It is not to follow his desires, but to keep himself in check, with a bridle, until his last day. This discipline, he writes, is teshuvah, and it is worth more than any amount of fasting or self-affliction. Its main place is the mouth. Every moment in which a person holds back his tongue, he earns a share of the hidden light that no angel or creature can imagine. The Gaon adds that one should refrain even from praising others, and certainly from speaking ill of them. And since habit rules over everything, this strength is built gently and steadily, from the earliest age, with words of kindness that settle in the heart.
Source: Iggeret HaGra, section 8 (printed in Alim LiTerufah, Minsk 5596)
Choose one situation today in which you usually say a little too much, perhaps a conversation about other people, a quick comment in a message or a reply made in frustration. When the urge comes, pause for a single breath and let the words go unsaid. Each time you do this, think of the Gaon's teaching that such a moment is a real gain. Start small and keep it up, because habit shapes the heart, and speech that is held back gently becomes easier to hold back the next day.