Question 111: Which is the third commandment?

Answer: The third commandment is, Thou shalt not take the name of the Lord thy God in vain: for the Lord will not hold him guiltless that takes his name in vain.

Question 112: What is required in the third commandment?

Answer: The third commandment requires, That the name of God, his titles, attributes, ordinances, the Word, sacraments, prayer, oaths, vows, lots, his works, and: Whatsoever else there is whereby he makes himself known, be holily and reverently used in thought, meditation, word, and writing; by an holy profession, andAnswerable conversation, to the glory of God, and the good of ourselves, and others.

Question 113: What are the sins forbidden in the third commandment?

Answer: The sins forbidden in the third commandment are, the not using of God's name as is required; and the abuse of it in an ignorant, vain, irreverent, profane, superstitious, or wicked mentioning, or otherwise using his titles, attributes, ordinances, or works, by blasphemy, perjury; all sinful cursings, oaths, vows, and lots; violating of our oaths and vows, if lawful; and fulfilling them, if of things unlawful; murmuring and quarreling at, curious prying into, and misapplying of God's decrees and providences; misinterpreting, misapplying, or any way perverting the Word, or any part of it, to profane jests, curious or unprofitable

Questions, vain janglings, or the maintaining of false doctrines; abusing it, the creatures, or anything contained under the name of God, to charms, or sinful lusts and practices; the maligning, scorning, reviling, or anywise opposing of God's truth, grace, and ways; making profession of religion in hypocrisy, or for sinister ends; being ashamed of it, or a shame to it, by unconformable, unwise, unfruitful, and offensive walking, or backsliding from it.

Question 114: What reasons are annexed to the third commandment?

Answer: The reasons annexed to the third commandment, in these words, The Lord thy God, and, For the Lord will not hold him guiltless that takes his name in vain, are, because he is the Lord and our God, therefore his name is not to be profaned, or any way abused by us; especially because he will be so far from acquitting and sparing the transgressors of this commandment, as that he will not suffer them to escape his righteous judgment, albeit many such escape the censures and punishments of men. (Here)

A lot of people seem to think that one disobeys this commandment only if and when he says "____ damn it," or "Oh, _____," or similar things.

But think momentarily of what it means to take a name, any name. When a woman gets married she takes the name of her husbands family and calls herself by it. The first thing it is to take God's name is to call him one's God. If you call God your God, then it better mean something; that is, the act of calling God (i.e., the God of Abraham, Isaac and Jacob, and the God and Father of the Lord Jesus Christ) your God comes not just with privileges, but also obligations.