The Seventh Commandment says, "You shall not commit adultery" (Exodus 20:14)
I am sure that everyone experiences a wandering mind sometimes, especially when driving. That is what I was doing as this train of thought passed through my own mind.
I was driving to church yesterday, a drive of thirty to forty minutes for me. I was listening to the radio, but I can't remember what the song was. I just remember that it was about a cheating spouse. I think that a wife, for example, who observes that a woman is flirting with her husband, should feel no need to intervene. She should be able to trust her husband to tell the interloper, "I belong to another; you'll have to take this business somewhere else." If he fails to respond in this way, then his wife has a controversy with him, not the other woman.
That thought led me to consider the subject of sin. If I am faced with temptation, my response must be that I belong to another, my Lord Jesus Christ, and therefore have no right to submit to that temptation, to sin, and to cuckold my divine Husband. If I fail to do so, then I have committed spiritual adultery, stolen what is properly His, and His controversy is with me.