The Theology of Thomas Watson Series: Part 9

One of the clearest differences between earlier Christians and many modern ones is how seriously they took sin.

Thomas Watson wrote in a time when believers spoke plainly about sin, confessed it honestly, and fought against it deliberately. Today, sin is often renamed, minimized, or explained away. We prefer words like weakness, struggle, or brokenness. Those words can be true, but they often soften what Scripture speaks plainly.

Watson would not have done that. He believed that sin was not merely unfortunate. It was destructive. It was dishonoring to God. And it was deadly to the soul if left unrepentant.

Yet Watson did not write about sin to produce despair. He wrote to produce repentance, humility, and gratitude for the grace of Christ.

Sin as an Offense Against God

Watson believed the seriousness of sin begins with who it is against.

Modern people often measure sin by its visible consequences. If no one is visibly harmed, the sin feels small. Watson measured sin differently. He measured it by the holiness of God.

In The Doctrine of Repentance, Watson writes:

Sin is a complication of all evils. It is the spirit of mischief distilled. It defaces God’s image, stains our glory, and brings the soul to ruin.”
— Thomas Watson, The Doctrine of Repentance

Watson understood that sin is not merely breaking rules. It is rebellion against the God who made us, sustains us, and calls us to Himself. Even private sins, unseen by others, are fully seen by God.

This perspective changes everything. Sin is no longer small just because it is common.

The Deceitfulness of Sin

Watson frequently warned that sin is dangerous not only because it is wrong, but because it is deceptive.

Sin rarely appears to us in its true form. It promises pleasure, freedom, relief, or control. It hides the cost and exaggerates the reward.

Watson writes:

Sin first deceives, and then damns.”
— Thomas Watson, The Doctrine of Repentance

That sentence is short, but it explains countless ruined lives. Sin persuades before it destroys. It convinces the mind before it hardens the heart.

Watson believed Christians must be especially alert here. A believer does not usually fall suddenly into serious sin. The fall begins in small compromises, tolerated thoughts, and quiet justifications.

This is why Watson urged believers to resist sin early, before it gathers strength.

Why Minimizing Sin Destroys Spiritual Life

Watson saw clearly that minimizing sin weakens the entire Christian life.

If sin is small, repentance becomes unnecessary. If repentance becomes unnecessary, grace becomes cheap. And when grace becomes cheap, holiness disappears.

In A Body of Divinity, Watson states:

Till sin be bitter, Christ will not be sweet.”
— Thomas Watson, A Body of Divinity

That statement is deeply pastoral. Watson is not calling believers to self-hatred or morbid introspection. He is reminding us that the beauty of Christ is seen most clearly when we understand what He has saved us from.

A shallow view of sin produces a shallow view of grace.

Sin Begins in the Heart

Watson consistently emphasized that sin is not merely external behavior. It begins in the heart.

In his exposition of the commandments, Watson shows that God’s law reaches thoughts, motives, desires, and intentions. Long before an action appears, the heart has already moved.

This is why Jesus speaks of lust as adultery in the heart and hatred as murder in the heart. Watson understood that the battle against sin must be fought inwardly, not only outwardly.

A man who only restrains behavior but never confronts desire will eventually fall.

Watson believed the Christian life requires honesty at this level. We must be willing to examine ourselves, confess what we find, and seek the Spirit’s help to change.

The Danger of Loving Sin

Watson made an important distinction between struggling with sin and loving sin.

Every Christian struggles. Even the most mature believers battle remaining corruption. But the direction of the heart matters.

Watson asserts:

A wicked man loves sin; a godly man hates it.”
— Thomas Watson, The Godly Man’s Picture

That distinction is crucial. The presence of sin does not prove a person is lost. But the love of sin without repentance should alarm any soul.

Watson believed one of the clearest signs of grace is not perfection, but a growing hatred of sin and a growing love for holiness.

Why Sin Hardens the Heart

Another theme Watson returns to often is the hardening effect of sin.

Sin never remains neutral. It either increases repentance or decreases sensitivity. A conscience ignored becomes quieter. Conviction resisted becomes weaker.

Watson warned that the most dangerous place a person can be is not in open rebellion, but in comfortable sin.

A man who feels no struggle, no conviction, and no urgency to repent is not spiritually healthy. He is spiritually numb.

Watson would urge such a person not to wait, not to delay, and not to assume there will always be another opportunity to turn back.

Repentance as a Lifelong Practice

Watson did not treat repentance as a one-time event at conversion. He saw it as a lifelong practice.

In The Doctrine of Repentance, he describes repentance as a grace that continues throughout the Christian life. Believers continue to confess, turn, and seek cleansing, not to be re-saved, but to walk closely with God.

Repentance keeps the heart soft. It keeps pride in check. It keeps the conscience sensitive.

A Christian who stops repenting soon stops growing.

Grace Does Not Make Sin Safe

Watson was deeply committed to the doctrine of grace. He preached justification by faith and the sufficiency of Christ. But he strongly rejected the idea that grace makes sin safe.

Grace does not remove the danger of sin. It removes the condemnation of the believer. Sin still damages fellowship, weakens assurance, and grieves the Spirit.

Watson believed that a right understanding of grace does not lead to carelessness. It leads to gratitude and careful obedience.

A heart that understands grace does not ask how much sin it can tolerate. It asks how closely it can walk with God.

Why Modern Christians Need Watson’s Clarity

Watson’s seriousness about sin may feel uncomfortable to modern readers. But that discomfort is often revealing.

We live in a culture that avoids guilt, resists accountability, and prefers affirmation over correction. That mindset easily seeps into the church.

Watson calls us back to reality. Sin is real. Holiness matters. Repentance is necessary. Grace is precious.

Without these truths, Christianity becomes sentimental and powerless.

A Final Word

Thomas Watson took sin seriously because he took God seriously. He took holiness seriously. He took eternity seriously. And he took the cross seriously.

A small view of sin always leads to a small view of Christ. But a clear view of sin makes the grace of Christ shine brighter.

We do not need to become gloomy or morbid. We need to become honest. Honest about our hearts. Honest about our need. Honest about the mercy that saves us.

Watson’s voice still calls us to that kind of honesty.

Transition to Week 10

If Watson teaches us to take sin seriously, he also teaches us something equally important: how to pursue holiness without becoming proud, strange, or spiritually arrogant.

That is where we go next.