Sin is never done in isolation. In fact, there are vertical, horizontal, and inward effects of it.
Vertical (offends God)
First and foremost, your sin — whether in act, attitude, or nature — is an affront to a holy God. “Against you, you only, have I sinned and done what is evil in your sight. . .,” (Psalm 51:4) King David says, after his adultery with Bathsheba and murder of Uriah. Before we talk about how sin hurts the people in your life or is a form of self-infliction, we must say that sin offends God. Commit one sin, and you are guilty of violating the entire Law (James 2:10). As born sinners (Psalm 51:5), sin doesn’t just involve the wrongs we commit (sins of commission), or right actions we neglect (sins of omission), but also involves our nature, our very being. We are totally depraved, born as rebellious, God-haters, self-lovers, glory thieves who rightly incur the wrath of God apart from a Savior. Of the five points of Calvinism, total depravity is the easiest to prove.
Horizontal (hurts people)
Sin is willful treason that offends a holy God but also hurts the people in your life. The more you sin, the more people you hurt. The more influence you have, the greater the effects your sin will have on others (hence, why it’s particularly hurtful when sinned against by a leader).
Let me say this a different way. Your unrighteous anger hurts your children. Your lust hurts your spouse. Your greediness hurts your team. Your pride hurts your country. Your stealing yours hurts your city. Your sloth hurts your organization.
Sin is never done in isolation. It has relational implications.
Consider Kind David again. David’s adultery and murder brought pain into the lives of Bathsheba, Uriah, the people under his command, the entire nation of Israel, and so on. Single men who stare at pornography are not scratching a private itch unseen by the world, but rather collect emotional baggage (to say the least) which worsens personal relationships. There is, of course, grace and hope available through Jesus, but our love for Jesus should spark motivation to kill sin and not be passive about it.
Inward (hurts yourself)
So sin not only incurs God’s judgment, and damages personal relationships, but sin also hurts you, the sinner. Seen this way, sin is self-infliction. It’s never the right choice. Those who truly belong to Christ have a desire to increasingly break free from sin and become more like Jesus. Far from a killjoy, growing in holiness is the path to true joy, the path to true flourishing. We were created to glorify and enjoy God and obey the demands of the covenant, but sin distorts this effort. Indeed, ongoing and unrepentant sin robs you of happiness, produces either conviction or guilt, and might distance God’s sense of fellowship with you.
So sin is a lose (offends God), lose (hurts people), lose (hurts you). Nobody is perfect. But if we think more deeply about the multi-dimensional impact of sin, we’d be more eager to avail ourselves to the means of grace to grow in love for our Savior and hatred of our sin.
When we ponder our sin, one cannot help but think of Paul’s words to the Romans: “Wretched man that I am! Who will deliver me from this body of death? Thanks be to God through Jesus Christ our Lord!” (Romans 7:24-25)