When God told the Israelites not to misuse his name, he was referring devaluing the holy name of God. The command was given in response to the practice that people had of taking oaths or swearing in the name of God to bolster their own character and integrity. Every time they used God’s name in vain, they caused the name of God to be depreciated. God’s holy name was and is to be reverenced. God’s name is not just a label. It’s an expression of his character.
When I was a kid, people would say things like “I swear on a stack of Bibles” or “I swear to God” to try to persuade others of their sincerity and honesty. Sometimes kids would say “I swear on my mother’s grave” or even “cross my heart, hope to die, stick a needle in my eye.” The kids that said those things were usually the kids who were the biggest liars in school.
The lesson here is that we are to be persons of such high character that we need not to invoke the name of God in order to be believable. If you are a person of character, you’re believable. If you’re not a person of character, you may try to use God’s name to make you appear to be something you’re not.
When Jesus got to earth, he restated the command this way, “Just say a simple, ‘Yes, I will,’ or ‘No, I won’t.’ Anything beyond this is from the evil one” (Matthew 5:37). What a great goal! Have such good character that people take your words at face value.