Have you ever sat by someone on the train or subway either talking on the phone or to someone else and just spewing out four letter words, I have. It’s pretty hard to sit through this kind of abuse for an hour, so thank G-d for noise-cancelling headphones.
In the beginning of the Torah portion of Kedoshim (Leviticus 19:20) we read an enigmatic instruction: ‘Kedoshim tihiyu - Be holy.’ This is different from the many other commandments before and after, which pertain to specific matters such as marital and ritual purity. The sages in the Sifri explain that the Hebrew word kadosh, which is normally translated as “holy,” actually means to be “distinct” or “separate.” Thus, these words are actually a commandment to separate ourselves.
The great Biblical commentator Rashi states that holiness is a direct consequence of not transgressing the prior sexual and moral prohibitions.
However Ramban - Nachmanides, states that this injunction of being holy includes not using disgusting speech, something that is not specifically prohibited in the Torah. Torah demands that a person go beyond the parameters it sets and live a life that is truly distinguished and uplifting. Using bad language can make a fine person into a crude one.
The Talmud Ketubot 8b speaks very harshly about someone who speaks in a vulgar way. “Whoever uses foul language even if there was a decree on them for seventy good years it will be changed into an evil decree.”
Rabenu Yonah in Shaarei Teshuvah states that using foul language runs against two of the fundamental character traits that we try to instill into ourselves: modesty and sensitivity.
Rambam – Maimonides states that the reason Hebrew is called a Holy Language is precisely because of its paucity of foul words.
Although we generally think of speech as just a superficial act, in truth, it has a strong impact on one’s inner self. The words that leave one’s mouth make an imprint on the mind and heart. No matter how fine and noble a character, a few rotten words can defile and corrupt a person. The flip side is also true. A crude person can become more refined if he or she improves the way he/she speaks. This is why shemirat halashon, “guarding one’s tongue,” is considered one of the first steps that need to be taken before correcting more serious character flaws.
Being careful that all words that leave ones mouth are holy is an important part of a living a “holy” life.