To grow in Torah and life it is most important to guard our tongue from saying evil. Here are some guidance to make us realize how the Mitzva of Shmirat Halashon (using our words for the good) is of paramount importance in Judaism.

1. « Who is the man who desires life (Heih’afetz Haim) and love length of days that he may see good? Keep your tongue from evil »
   (Psalm 34,13)  
   
   
2. « The love that Hashem has on Bnei Yisroel is conditional on the amount of love Bnei Yisroel has for each other. The more Bnei Yisroel loves each other the more Hakadosh Baruch Hu will love us »
   (Mesilat Yesharim 19).
   
   
3. « The people which I formed for Myself, that they might tell of My praise » (Yecha’yahou 43, 21).
   Hashem created the Jewish people to publish His glory through prayer, study of Torah and other Mitzvot whose instrument is the mouth. Indeed, the mouth defines the Jewish people.
   
   
4. « When a man keep his mouth, it is compared to a utensil of the temple ».
   
   
5. « Nothing we say is lost, and everything is registered. Angels are send to every human being to record all his words and they never leave him. “For the bird of Heaven may carry your voice, and the angels may report what you say » (Koheleth 10,20) (Letter excerpt from Gaon de Vilna).
   
   
6. « Whoever speaks Lashon Hara magnifies his sins up to the Heaven » (‘Arakhin 15b).
   
   
7. « There are those that make themselves rich, yet have nothing » (Proverbs 13,7).
   
   
8. « Just as people’s faces don’t resemble each other, so to their thought processes don’t resemble each other  » (Bamidbar Rabba 21,2).
   
   
9. Hashem tells Israel: « My dear children, what is the quality that I ask of you? To love one another and respect each other » (Tana debei Eliyahu, chapter 28).
   
   
10. Keep your tongue from evil and your lips from deceitful speech …
    
    
11. « Those who guard their lips preserve their lives, but those who speak rashly will come
    to ruin »
    (Proverbs 34, 13-14).