You shall not misuse the name of the Lord your God, for the Lord will not hold anyone guiltless who misuses his name. Ex. 20:7, N.I.V.
The United States has trade laws to protect the consumer from the fraudulent use of brand names on merchandise that is not in truth manufactured by the companies that own the names. In this way both unsuspecting buyers and manufacturers can seek redress if poor quality merchandise is spuriously marketed as "the real thing." Peddlers of such bogus products are often fined heavily and ordered to make restitution to the offended parties.
If you've ever been on the receiving end of this kind of dealing, you know how annoying and sometimes damaging the results can be. The car part that gave out halfway to Iowa; the epoxy glue that let go just as you lifted a mended hot-drink mug to your mouth. But what if the "product" is God? What if the "truth" accepted doesn't get you all the way to heaven? What if your "mended life" gives out on you, scalding you with feelings of hopelessness and despair?
When we "trade" in religion, our fair-minded God has indicated that we need to be scrupulously careful about what we present as "the real thing." So much is at stake! Our view of God ultimately decides our eternal destiny! If God's name is attached to concepts that leave us inadequately prepared to meet the rigors of this life, we will come to believe that He is inadequate! If His name is used as authority for emotional abuse, we will learn to hate Him! If in His name we are plundered of our dignity and made to submit to mindless humiliation, we will never rise to the heights of godly attainment afforded us by our excitingly visionary Maker.
We can trust God. He guarantees that His ways will bring us happiness, and we may trust that the guidelines that bear His name will ultimately do just that. However, when offered such "truth," we are encouraged by God Himself to look for His "brand name" before accepting it. "To the law and to the testimony! If they do not speak according to this word, they have no light of dawn" (Isa. 8:20, N.I.V.).
The third commandment underscores that God cares a great deal about the integrity of our thinking. He desires to lead us away from the slave mentality of Egypt and into reasoning like the sons and daughters of God that we were destined to be.