The Second Commandment
“You shall not make wrongful use of the name of the Lord your God, for the Lord will not acquit anyone who misuses his name. ~ Exodus 20:7
"We should so fear and love God as not to curse, swear, practice magic, lie, or deceive by his name, but call upon him in every time of need, and worship him with prayer, praise, and thanksgiving." ~ Martin Luther
What's so big about a name?
We aren't really even sure what God's name actually is! Some of the names we've gotten from scripture are: Yahweh, El Shaddai, Elohim, Adonai. Then we've also got Jehovah, and Lord.
Add Jesus to the mix and we have his first name, his title (Christ), both together, and a bunch of his titles: Bread of Live, Prince of Peace, etc.
Why is this so important to God?
Luther gives us a good clue here: God's names (and Jesus') are meant for praise and prayer. Not in anger or curses.
You can take it down to the easiest level as well. How do you feel when your own name is either mistaken or misused? When someone calls you a name? When someone calls you someone else's' name?
I think lately of the term "she's a Karen," in reference to middle class white women whose rude behavior stems from her privilege. How does that make the Karens of the world feel? (for males, the equivalent is "Ken"). I don't know about you, but I know a lot of nice Karens and Kens, and I also know the cringe-worthiness they feel when their name is used this way.
Names can be used as slurs and jokes.
Is it any wonder why God would want to protect the most holy of all names?
Going back to what God's name truly is, I think the breadth of names God has give us the perfect example of HOW to use God's name: each name God has in Hebrew scriptures is a testament to God's glory! Each name is prayer and praise in and of itself.
A Prayer by Martin Luther: Dearest God and Lord, strengthen and uphold us in your pure, precious Word through Jesus Christ our Lord, and help us to show and live our thanks with our fruits of faith to your praise and thanks forever. Amen.