Whenever someone commits an atrocious act—be it cheating on their spouse, stealing from someone they trust, or even committing murder—one of the most common responses you hear is: “I just don’t understand how a person could do such a thing.”
It’s said as if the speaker is so morally superior, so far removed from wrongdoing, that they can’t even comprehend such actions.
But this statement isn’t virtuous; it’s naive.
Worse, it’s dangerous.
Recognizing Our Capacity for Evil
To say that you can’t understand how someone could do something evil reveals a lack of self-awareness.
Every one of us is capable of great evil, given the right circumstances.
The human condition is such that we are susceptible to moral decay, and we need to be sober-minded about this reality.
If we don’t recognize our own potential for wrongdoing, we can’t take the steps necessary to defend against it.
It’s easy to believe that heinous acts are the result of “monsters”—people fundamentally different from us. But the truth is, evil often grows gradually.
A good person doesn’t suddenly wake up one day and decide to destroy their life or harm someone else.
There’s a process, a slow erosion of morals and values that leads them to that point.
If we fail to see that, we’re leaving ourselves vulnerable to the same fate.
The Step-by-Step Descent into Sin
Consider adultery.
People often think affairs happen in a moment of passion, as though a married person suddenly “snaps” and betrays their spouse.
But that’s not the case.
Adultery is a process—a gradual drift away from a once-strong marriage, often fueled by unmet emotional needs, stress, or the slow erosion of communication and affection.
Here’s how it happens:
It begins with small moments of neglect. Maybe a husband and wife stop spending quality time together, or they get caught up in work and life’s demands.
Resentment starts to grow in little ways—he feels underappreciated; she feels unheard.
Then, there’s an attractive coworker who shows interest—an innocent compliment, a friendly lunch.
At first, the husband thinks nothing of it. But soon, that external attention becomes more exciting than what he’s getting at home.
Little by little, boundaries are crossed.
What started as an innocent conversation turns into an emotional connection, and soon, physical infidelity.
Very few people plan to cheat.
Adultery is the result of dozens of unchecked decisions, all of which feel harmless in the moment but, together, lead to disaster.
It’s a slow slide, not a single leap.
The Same Process Applies to Other Sins
Adultery is just one example. This slow moral decay can apply to almost any kind of sin.
1. Theft: Stealing often starts small—a dishonest expense report, taking credit for someone else’s work, pocketing a few extra dollars from the till. Each small act of dishonesty desensitizes the person to larger thefts. Before long, they’re engaging in behavior they never thought they would.
2. Murder: Most violent crimes aren’t sudden, spontaneous acts of rage. They often begin with unresolved anger, grudges, or jealousy. As bitterness grows, the individual becomes less and less concerned with the consequences of their emotions. They let their anger fester until, in a moment of rage, it spills over into violence.
3. Lust and Addiction: Lust doesn’t erupt out of nowhere. It begins with small indulgences—a second glance, inappropriate flirting, pornography. Over time, these “small” sins escalate, until they lead to full-blown infidelity or addiction. The same goes for substance abuse or any addictive behavior—it starts with one small compromise and snowballs.
In all these examples, sin is not an isolated incident. It’s the result of a process—a gradual decay of character, a series of small decisions that go unchecked.
Planning Ahead: How to Stop Sin Before It Starts
The real danger of saying “I don’t understand how someone could do that” is that it prevents us from learning the necessary lessons to guard ourselves against the same failures.
We must understand how a person could get to that point—because that person could be us.
Recognizing our own capacity for evil allows us to create strategies to prevent it.
Wisdom is the ability to look ahead, to foresee potential pitfalls, and to take active steps to avoid them.
Proverbs 22:3 says, “The prudent see danger and take refuge, but the simple keep going and pay the penalty.”
Identifying Our Own Weaknesses
We need to ask ourselves tough questions.
What are the situations, thoughts, or people that could lead us to compromise our morals?
What circumstances might tempt us to commit a sin we never thought we would?
• Could unresolved conflict in my marriage lead to emotional infidelity?
• Could unchecked anger or jealousy drive me to harm someone I care about?
• Could stress and financial pressure make me cut corners, cheat, or steal?
These aren’t pleasant questions, but they are necessary.
By thinking through these scenarios now, we can set up boundaries and guardrails that prevent us from ever getting to that point.
It’s far easier to avoid sin when you recognize the warning signs early on, rather than when you’re already halfway down the path.
Cultivating a Strategy Against Sin
Much like a general on the battlefield, we need to be strategic in our lives.
It’s not enough to think that we’ll be able to resist temptation when it comes.
We have to plan ahead, identify potential weaknesses, and cut off the opportunities for sin before they arise.
Christ himself emphasized the importance of cutting sin off at its root. When He spoke about lust and anger in the Sermon on the Mount (Matthew 5), He wasn’t just warning us about the acts of adultery or murder—He was teaching us that sin starts in the heart.
If we allow lust, anger, or bitterness to take root, it will eventually grow into full-blown sin.
The key is to uproot those seeds early, before they take hold.
Understanding Is the First Step to Prevention
The next time you hear someone say, “I don’t understand how a person could do such a thing,” recognize it for what it is: a dangerous lack of awareness.
If we don’t understand how sin happens, we can’t defend ourselves from it.
We are all capable of great evil, and we all have breaking points.
The wise person doesn’t assume they’re immune to sin.
Instead, they take proactive steps to identify potential risks and set up defenses. They understand the slow, subtle process that leads to moral failure, and they work diligently to cut it off before it ever begins.
Understanding our capacity for sin is the first step to preventing it.
Recognize the danger, strategize against it, and never assume you’re above it.
It’s only by accepting the reality of our own potential for evil that we can guard ourselves from falling into it.