The Second Commandment
The Large Catechism
Just as the First Commandment instructs the heart and teaches faith, so this commandment leads us outward and directs the lips and tongue into a right relationship with God. For the first things that burst forth and emerge from the heart are words.
It is a misuse of God’s name if we call upon the LORD God in any way whatsoever to support falsehood or wrong of any kind. What this commandment forbids, herefore, is appealing to God’s name falsely or taking his name upon our lips when our heart knows or should know that the facts are otherwise” for example, when taking oaths in court and one party lies about the other.
"But above all, my brothers, do not swear, either by heaven or by earth or by any other oath, but let your “yes” be yes and your “no” be no, so that you may not fall under condemnation."
"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.” 14 Seven sons of a Jewish high priest named Sceva were doing this. 15 But the evil spirit answered them, “Jesus I know, and Paul I recognize, but who are you?” And the man in whom was the evil spirit leaped on them, mastered all of them and overpowered them, so that they fled out of that house naked and wounded."