כָּב֣וֹד לָ֭אִישׁ שֶׁ֣בֶת מֵרִ֑יב וְכָל־אֱ֝וִ֗יל יִתְגַּלָּֽע׃
C’est l’honneur de l’homme de se tenir loin des disputes; mais tout sot s’y jette à corps perdu.
Rabbeinu Bahya
The word והתקדשתם, may also be understood in terms of פרישות, asceticism, introversion, abstinence. Anyone who displays abstinence from the pleasures this world has to offer is considered holy, קדוש. Similarly, our sages in Torat Kohanim Sifra Shemini 12,3 explain the verse simply by reversing these words and translating: “just as I am holy, I want you to sanctify yourselves. Just as I am ascetic, separate, I want you to practice similar traits.” The idea is that man should try not to indulge in any of the cravings which are natural to him unless they are vital for his health and well-being. When someone manages to deny himself all the physical gratifications which are permissible but not necessary for his health and well-being he is called קדוש, holy. Anyone however, who indulges bodily cravings over and beyond the necessary minimum is called כסיל, “fool.” The more one indulges physical cravings the greater the likelihood of committing infractions of Torah law (compare Proverbs 20, 3). This is why the Torah had to write the instruction “sanctify yourselves!” Restrictions that are desirable do not only include too much food and drink and marital relations with one’s wife, but also excess use of one’s mouth for unnecessary conversation. This is why Solomon said in Proverbs 15,2: “the tongue of the wise uses knowledge properly; the mouths of fools express folly.” Solomon continues immediately, warning: “the eyes of G’d are everywhere; they behold both the good and the wicked.” He meant that G’d’s supervisory stance is such that people guilty of offending speech may expect to pay the price. The prophet Isaiah 9,16 deals with the same subject when he said: “that is why my Lord will not spare their youths, nor show compassion to their orphans and to their widows; for they are all ungodly and wicked and every mouth speaks impiety.” The reason the prophet singles out the youths, the immature in years, is that they more than older people are guilty of such abuse of the power of speech. The Talmud Shabbat 33 remarks on the subject of improper use of one’s power of speech that anyone guilty of this sin will experience that he will sink even lower inside gehinom, purgatory. They base this on Proverbs 22,14: “the mouth of the immoral woman is a deep pit; he who is doomed by the Lord will fall into it.” We also find that the prophet Ezekiel has something pertinent to say on this subject in Ezekiel 35,10: “because you said: ‘the two nations and the two lands will be mine and we shall inherit them!’ But Hashem was there.” The prophet goes on to threaten retribution for such abuse of one’s mouth, telling us that G’d is mindful of such boasts.