There is much talk about private sin, that if your sin doesn’t hurt anyone then don’t worry about it.
This sounds nice, but it’s really bad advice.
Sin is selfishness. Sin, in whatever form, is putting your needs first. What makes sin bad is that you put your will ahead of God’s will, your desires above His.
The natural corollary to this is that if you put your will and desires ahead of God’s you are also putting it ahead of everyone else.
The first commandment is to love the Lord your God, the second is much like it, love your neighbor as yourself. If any one says he loves God and yet does not love his brother, he is a liar.
Sin is the killer of love.
“And because iniquity shall abound,
the love of many shall wax cold.”
Sin, whether you get caught or not, in fact, whether it’s just in your head or acted upon, kills love. When iniquity abounds; love shrivels and dies.
You may think that what you do behind closed doors, in the privacy of your own room, or even the privacy of your own head, doesn’t really matter cuz it doesn’t hurt anyone, but you are wrong.
Love is the ultimate NT virtue, the point of the Law, because love shows a lack of sin.
This is simple and yet profound. I wish I could deepen it further for you, but I can’t.