This is probably the least thought of commandment out of all of them because the world has become desensitized to it because of books, movies and people in general.

God's name and his character are inseparable.

Using his name in vain,empty or useless manner is insulting.

To perjure oneself in court of law or by cursing.

However, this commandment also applies to hypocritical worship, using God's name in meaningless prayer and praise.[Is.29:13]

In the Jewish Torah it says[EX.20:7] "You are not use lightly the name of Adonai your God because Adonai will not leave unpunished someone who uses his name lightly.

I wonder if the ones who claim to be able to heal and do it in the name of God and nothing takes place would be in vain ?