Our words mean things. What we say is a reflection of our heart. G-d warns us that when we make a vow we must do what we say.
G-d has given me stern warnings about my tongue. HE has told me “don’t ever speak to me that way again.”
The power of life and death is in the tongue. G-d created the earth with ten utterances. This means what I say has an effect on very life itself.
HaShem told me control your tongue.
I am learning how to do this.
[G‑d instructed Moses to tell the Jewish people,] “If someone makes a vow to G‑d . . . he must not violate his word.” Numbers 30:3
The Rebbe explains The word for “violate” in Hebrew (yacheil) comes from the word for “profane” or “unholy” (chol). The inner meaning of this verse is therefore that we should not make our words “unholy”; even our mundane conversation should be imbued with holy intentions and be consistent with the greater purpose of Creation, making a home for G‑d in this world.1Likutei Sichot, vol. 13, p. 108