Swearing - verbal misrepresentation of God. How we take God's name in vain. Jesus forbids oaths altogether. Some circumvented truth by avoiding God's actual name. The truth, the whole truth, and nothing but the truth.
Every promise is sacred, and irreverence is blasphemy.
In the second commandment, worshiping the true God in a false manner is forbidden. This describes the essence of idolatry. A. Easy to preach on. B. Hard to preach on - if we are honest. God denounces idolatry.