There is a concept in Judaism that our bodies are holy. R Meir Baal HaNais, the Tanna who codified the Mishnah, said “bein kach v’bein kach banim atem l’Hashem” – you are a child of Hashem, regardless of how you live your life. R Meir is telling us that not only are our souls holy, as one might think, but that our physical bodies are also receptacles of holiness. This means that our lips, our tongues, our voice boxes, our tracheas – every part of our bodies that allows us to speak – are holy.
There is another concept that says zeh l’umat zeh – there is an equivalency for everything in the world. For every portion of holiness God put into this world, there is an equal portion of its opposite. Otherwise, free will would be impossible. From here we can infer that we have two choices: to use our ability to speak for the good and bring more holiness into the world, or abuse our speech and push holiness away.
If we knock ourselves down with our words and tell ourselves that we’re ugly and worthless and a waste of space, we are pushing holiness away, throwing it into the trash and running off. Another equally bad mistreatment of this holiness would be to knock others and call them those horrible epithets.
To harness the holiness in your speech and use your words for the good, you can build yourself up and call yourself beautiful, worthy, brilliant, someone who can and will change the world. Giving others those compliments will also accomplish the same goal. Even if you don’t believe that you actually are those things, I promise that you are, even if you can’t see it now. Say it anyway. Eventually, you’ll realize the truth.