The Third Commandment is "Thou shalt not take the name of the Lord thy God in vain."
In otherwords, "Do not lift up, use, or appropraite the word by which you distinctively know God in ways that lack purpose, value or truth."
God said to Moses, "I am that I am." From Hebrew, "Yod-He-Vav-He" transliterated into English: YHWH, with vowels added "Yahweh". Translated, I am who I am, or I will be that I will be, He who IS, the self-existent one, The Great I AM.
From the limited realm of language, these naems are intended to reaveal the fullness of God's being, nature, attributes and everything that can be known. The main concept here has to do with the elusive term "being". Some things are, while others are not. If you want a fancy word, this is an ontological issue--the branch of metaphysics that studies the nature or existence of being.
The name of God embodies all matter, energy, life, and truth. A name points and refers and distinguishes; brings to mind; a name carries with it personal history; power and authority; reputation.
The third commandment says, in substance, in principle, that you cannot take the name of the Lord in vain. You use the name of God whenever you believe in something. What you really believe in, you are attributing to God and experiencing as God. And that shapes the reality of your daily life experiences.
By the power of your thoughts you re-present your idea of God. How would your life change if you believed that your search for God was like a fish in search of water? What would it be like to really believe in the goodness, and mercy, and love, and omnipresence of Source itself...to be at one with that and see it reflected back to you...to find peace and joy by just breathing the air?
You cannot use the name of the Lord in vain. You cannot.