"The Third Commandment forbids taking the Lord's name in vain. God does not want us to empty his name of its meaning or use it in a careless or wicked way. The Old Testament had a broad catalog of sins that were seen as violations of the Third Commandment . . . Clearly the Third Commandment concerned more than just the use of the tongue. Wherever the people or things that belonged to the Lord were defiled, the Lord - whose name they bore - was also dishonored and the Third Commandment broken." Kevin DeYoung. The Good News We Almost Forgot. 171. 

Question 99: What God's will for us in the Third Commandment?

Answer: That we neither blaspheme nor misuse the name of God by cursing, perjury, or uneccessary oaths, nor share in such horrible sins by being silent bystanders. In a word, it requires that we use the holy name of God only with reverence and awe, so that we may properly confess Him, pray to Him, and praise Him in everything we do and say.

Question 100: Is blashpemy of God's name by swearing and cursing really such serious sin that God is angry also with those who do not do all they can to help prevent it and forbid it?

Answer: Yes, indeed. No sin is greater, no sin makes God more angry that blaspheming his name. That is why He commanded the death penalty for it.