The issue of the 3rd commandment cropped up on David Wood's Facebook wall. Wood recommend the new movie Unbroken.
A commenter asked if characters in the film took the Lord's name in vain. He said he'd walk out on a movie where that happened.
This raises several issues. What does the 3rd commandment actually prohibit?
i) One popular interpretation considers this a taboo against using "God," "Christ," or "Jesus" as an expletive, or using the Lord's name flippantly (e.g. "OMG).
No doubt that's a misuse of God's name. An irreverent use of God's name.
However, it trivializes the prohibition to think that's the only thing or primary thing it forbids.
ii) Even if the 3rd commandment is a prohibition against profanity, it would be a prohibition against speaking profanity, not hearing profanity.
iii) Another traditional interpretation, both in Jewish circles and Reformed circles, is to construe it as a prohibition against breaking a religious oath. There are, however, two possible problems with that interpretation:
a) We already have a prohibition against perjury in the 9th commandment. If the 3rd commandment is similar, that's redundant. Likewise, why would two related prohibitions be separated by several other prohibitions? Why not combine them?
b) Coming in the heels of the first two commands, which concern with false worship, it would be logical if the 3rd commandment is conceptually related to false worship.
iv) Apropos (iii-b), the prohibition may well have specific reference to the occultic use of God's name. In the ancient world it was customary to invoke the name of a deity in witchcraft and divination, as a way of summoning the deity's power and authority.
That's not an interpretation which occurs to most modern western readers, because that's not a feature of our common experience. However, in parts of Africa and Brazil (to name two examples), where black magic is prevalent, that's very much a live issue.
Apropos (iv), the incident in Acts 19:13 is a good illustration of what the 3rd commandment prohibits:
Then some of the itinerant Jewish exorcists undertook to invoke the name of the Lord Jesus over those who had evil spirits, saying, “I adjure you by the Jesus whom Paul proclaims” (Acts 19:13).
There a Jewish exorcist invokes the name of Jesus to conjure his authority. That's a misuse of the name, because the exorcist is not a Christian.