What Is Sin?

If you are like me, you are not looking for a deep theological answer to the nature of original sin or a breakdown of the Greek word. You want to know where the line is, and whether you have already crossed it.

We were raised with a basic idea of right and wrong, and most of us were taught the basics of what it means to be a good human being. That's why I was surprised to learn that the most-searched theological question on Google is "What is sin?" It made me wonder why.

The Question Behind the Question

I can't speak for everyone who searched for this question, but I can explain why I find myself asking it. I am a Bible scholar, and I can give you the academic definition of sin. But to be honest, the times this question comes up for me are not when I'm in an academic discussion, but when I feel the Holy Spirit prompting my heart that I'm moving into grey areas that might lead me away from God. This normally happens when I know the Spirit is directing me to do something and I feel reluctant. Then I wonder: is it a sin not to do it? Or when I must act according to the self-giving example of Christ, but all I want to do is assert my own way. And I convince myself I'm justified, because my decision isn't found on any list of sins in the Bible. However, if we look at the whole story of the Bible, we see that sin is not about failing to stick to a predetermined list. Rather, it's about choosing paths that lead us away from God.

What the Gospel of Mark Teaches Us

I like the way the Gospel of Mark deals with this question. Mark doesn't give us complicated definitions. Instead, he tells us stories that help us understand the nature of sin and the character of Jesus, the Holy One of God, who can forgive our sins. He shows us what it looks like through the unfolding story itself; through conflict, resistance, repentance, and forgiveness.

The word first appears in chapter 1, when John the Baptist preaches "a baptism of repentance for the forgiveness of sins" (1:4). It clusters most densely in Mark 2:1-12, where it appears four times in five verses, right at the moment Jesus forgives a paralyzed man and the religious leaders take offense.

In Mark's gospel, sin is not first a list of broken rules, though we can find such lists elsewhere in the Bible. Mark's stories show us that sin is a broken relationship with a holy God. How can we reach this conclusion? Mark begins by telling us about John the Baptist, a prophet like those we read about in the Old Testament. And like the prophets, his message is to repent, turn back to God, and be baptized for the forgiveness of sins. So we can see that sin is turning away from God.

We see this again in the identification of Jesus as the Holy One of God. Scripture calls all kinds of things holy: people, places, objects, even Israel itself. But God is the source and measure of all holiness; everything else is holy only because it belongs to him or is set apart for him. That's what makes the title "the Holy One of God" so significant: it places Jesus in an extraordinary relationship to God's own holiness, as the one who can make others holy too.

Another clue is the conflict between Jesus and the religious leaders. Their sin was not disagreeing and arguing with Jesus; it was that they hardened their hearts. They refused to accept God's invitation, in Jesus, to a renewed covenant relationship. Their sin was their stubborn refusal to believe and accept Jesus as the Messiah who came to restore and deliver the people of Israel. So the stories Mark tells teach us that sin is the refusal to believe and receive Jesus as the holy Son of God, who restores our relationship with the Father. The sinful things we do aren't disconnected violations on a checklist; they reveal and deepen this rupture in our relationship with God and others.

The Beginning of Resistance

Mark 2:1-12 is where this resistance begins to surface. The religious leaders are in the presence of Jesus, the Son of God; they hear his words, watch him heal, and witness his authority. But instead of wondering at it, they start questioning him in their hearts. It's the first crack, not yet the full break. As Mark's story continues, that questioning hardens into open opposition until, by chapter 3, the leaders are plotting to destroy him. The pattern is questioning, then resistance, then hardened hearts, then rejection. And that unavoidable drift is what separates a person from the God who keeps coming toward them.

What Jesus' Forgiveness Reveals

But Mark 2 isn't only a story about resistance; it's a story about authority to forgive. Before the religious leaders object to anything, Jesus looks at a paralyzed man carried in by his friends and says, "Son, your sins are forgiven" (2:5). He says this before the healing, before any proof, before the man does anything to earn it. The scandal isn't that Jesus heals; it's that he forgives. This is something the leaders rightly recognize only God can do. That's the astonishing claim underneath this whole episode: the Holy One of God doesn't just diagnose our brokenness; he closes the distance it creates. Sin separates us from God, but in Jesus, God comes toward sinners with the authority to restore what's broken.

Two Verses for the Grey Areas

So how does that translate to us today? Jesus gave us his Holy Spirit to guide us, and if we live in attentive fellowship with him, he will direct us through the grey areas that tend to confuse us. There are two verses that help me when I'm in doubt.

The first is Romans 14:14, which says:

"I know and am persuaded in the Lord Jesus that nothing is unclean in itself; but it is unclean for anyone who thinks it is unclean."

A related verse in the same chapter is Romans 14:23:

"But whoever has doubts is condemned if they eat, because the eating is not from faith; for whatever does not proceed from faith is sin."

These verses are about food laws, so they're not about obvious sins like murder or lying. Paul isn't handing the Roman church a rule of personal preference, though he's writing to a community where believers genuinely disagreed, and his concern is faith, conscience, love, and not causing another believer to stumble. The principle isn't "if I feel okay about it, it isn't sin." It's that Spirit-led discernment in the grey areas is shaped by Scripture, the character of Christ, love of neighbor, and life in Christian community, not just an internal feeling that something is fine for me.

So, as I walk in that kind of relationship with Jesus and his people, his Spirit guides me to recognize temptation and to protect what matters most: my relationship with God.

So, What Is Sin?

Back to the question everyone's Googling: sin isn't a checklist to measure yourself against; it's the state of a relationship. But that's not where the story ends. The same Jesus who exposes hardened hearts is the one who says, "your sins are forgiven," before we've done anything to deserve it. So the real question isn't just "did I cross a line," it's "am I staying close to Jesus, the Holy One of God, who has authority to forvige sins."

We dig into this more in Season 5, Episode 2. Give it a listen, and let us know in the comments: what grey area is the Holy Spirit nudging you about this week?