While looking over the Ten Commandments, one should regretfully notice how the Commandments are so easy to break. The first Commandment being "Thou shall have no other god but me" and the second "You must not make for yourself an idol." Unfortunately, the third Commandment is also one that far too many people refuse to pay attention to.
Exodus 20:7, "You must not misuse the name of the Lord your God" (NLT). Most people understand blasphemy to be saying words against God, for example, one may hear an athesit or agnostic person saying, "There is no such thing as God." Even though Christians may not say these same words, they are still blaspheming God's name on a regular basis. Everyone has either said or heard the quote so often used, "I swear to God on the Holy Bible" or even, "If I am wrong, may God strike me with lightning now."
First and foremost, do you really want God to strike you with lightning? What would happen if he did, would you then be mad or upset? God is worthy of praise. It is not neccesary to use His name otherwise. If you are trying to convince people of your honesty, you have a problem. It probably means you are not a very trustworthy individual and you are finally having to do all you can to convince people that you are actually being honest. God says, to "let your yes's be yes and your no's be no". There is nothing more that we need to do when we live according to God's word.
God found this to be a very important law. He made it the third Commandment, even before murder. So many people drag the name of God through the mud. God is so powerful and so mighty, that humans have no need to even say his name unless it is in worship or praise. God can save a human who has sinned against other humans, but sinning against God himself is a major blow. Just like when kids talk about other kids' parents, the defenses get high. Would one actually want to say something about the name of God, the one who is the parent to EVERYONE? Consider this the next time you are having a casual conversation with friends, and the next time anyone mentions being struck by lightning, perhaps you should get up and move.