Exodus 20:7 You shall not take the name of the LORD your God in vain, for the LORD will not hold him guiltless who takes his name in vain.

Because God's name reveals God's glory, we must honor His name in all that we say and do.
      I. God's name reveals who God is
    II. God's name must never be treated as empty
   III. God's people are called to hallow God's name
 

Westminster Larger Catechism
Q. 111. Which is the third commandment?
A. 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 taketh his name in vain.

Q. 112. What is required in the third commandment?
A. 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, and answerable conversation, to the glory of God, and the good of ourselves, and others.

Q. 113. What are the sins forbidden in the third commandment?
A. 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 any wise 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.

Q. 114. What reasons are annexed to the third commandment?
A. The reasons annexed to the third commandment, in these words, The LORD thy God, and, For the LORD will not hold him guiltless that taketh 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.

Heidelberg Catechism
QUESTION 99.
What is required in the third commandment?
Answer. That we, not only by cursing or perjury, but also by rash swearing, must not profane or abuse the name of God; nor by silence or connivance be partakers of these horrible sins in others; and, briefly, that we use the holy name of God no otherwise than with fear and reverence; so that he may be rightly confessed and worshipped by us, and be glorified in all our words and works.
QUESTION 100.
Is then the profaning of God's name, by swearing and cursing, so heinous a sin, that his wrath is kindled against those who do not endeavor, as much as in them lies, to prevent and forbid such cursing and swearing?
Answer. It undoubtedly is, for there is no sin greater or more provoking to God, than the profaning of his name; and therefore he has commanded this [g] sin to be punished with death.