Untitled Sermon

“Today, If You Hear His Voice”

A Sermon on Hebrews 3:7–19 — The Danger of False Conversion

Introduction: A Warning to the Visible Church

The passage before us is not addressed to pagans, but to those within the covenant community—those who have heard, who have seen, who have professed. And yet, many of them perished in unbelief.

This is one of the most sobering doctrines in Scripture: Not all who appear to belong to Christ truly belong to Him.

As Jesus Himself says:

“Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven…” (Matthew 7:21, ESV)

This text exposes the terrifying reality of false conversion.

I. Hebrews 3:7–11 — The Voice of God and the Danger of a Hardened Heart

“Therefore, as the Holy Spirit says, ‘Today, if you hear his voice, do not harden your hearts as in the rebellion…’”

Notice the urgency: “Today.”

God is not silent. The Holy Spirit is presently speaking through His Word. But the warning is equally urgent: Do not harden your heart.

A hardened heart is not ignorance—it is resistance to known truth.

Israel had extraordinary privilege:

“Your fathers put me to the test… and saw my works for forty years.”

They witnessed miracles, deliverance, and provision. Yet God says:

“They always go astray in their heart; they have not known my ways.”

Here is the tragedy of false conversion:

Exposure without transformation

Knowledge without submission

Religion without relationship

As Charles Spurgeon warned:

“A man may go to hell with a Bible in his hand, if he has not Christ in his heart.”

And the result is sobering:

“As I swore in my wrath, ‘They shall not enter my rest.’”

God’s patience does not cancel His justice. A hardened heart, left unchecked, leads to final exclusion from His rest.

II. Hebrews 3:12–13 — The Hidden Danger Within the Church

“Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God.”

This warning is directed to:

“brothers”

It is a warning inside the church, not outside it.

The danger is deeply personal:

“lest there be in any of you…”

A false convert may sit under faithful preaching, participate in church life, and yet possess:

“an evil, unbelieving heart”

The core issue is not behavior alone—it is unbelief.

And this unbelief is subtle:

“that none of you may be hardened by the deceitfulness of sin.”

Sin deceives by:

Minimizing guilt

Imitating true faith

Offering false assurance

As R.C. Sproul observed:

“The same sun that melts wax hardens clay.”

The same gospel that saves some will harden others who continually resist it.

This is why the church must be active in mutual care:

“Exhort one another every day… as long as it is called ‘today’”

False conversion often flourishes in isolation, but is exposed through faithful exhortation.

As Thomas Watson said:

“Sin is a flatterer that kills.”

III. Hebrews 3:14–15 — The Evidence of True Conversion

“For we have come to share in Christ, if indeed we hold our original confidence firm to the end.”

This verse does not teach that perseverance earns salvation—but that it proves it.

True conversion is marked by:

Enduring faith

Continuing trust

Persevering confidence

Not perfection—but persistence.

False conversion may begin with enthusiasm but fades under pressure.

Jesus describes such people:

“Yet they have no root in themselves… and when tribulation or persecution arises… they fall away.” (Mark 4:17, ESV)

The distinguishing mark of genuine faith is not its beginning, but its continuance.

Again the Spirit repeats:

“Today, if you hear his voice, do not harden your hearts…”

Why repeat it? Because the danger is constant. Every hearing of the Word either:

Softens the heart, or

Hardens it further

As John Owen wrote:

“There is no such thing as standing still in our relationship with God.”

IV. Hebrews 3:16–19 — The Root Cause: Unbelief

“For who were those who heard and yet rebelled? Was it not all those who left Egypt led by Moses?”

The answer is devastating: The very people who experienced redemption from Egypt.

“And with whom was he provoked for forty years? Was it not with those who sinned, whose bodies fell in the wilderness?”

They had:

Seen God’s power

Received His provision

Heard His promises

And yet:

“So we see that they were unable to enter because of unbelief.”

This is the final diagnosis of false conversion: Unbelief masked by outward association.

Not ignorance. Not lack of exposure. But refusal to truly trust God.

As Jonathan Edwards observed:

“The devil has a greater degree of speculative knowledge of God than any man.”

A person may:

Affirm doctrine

Participate in church

Express religious emotion

And still lack saving faith.

John Owen rightly said:

“Unbelief is the great damning sin where the gospel is preached.”

Conclusion: A Call to Respond Today

The repeated word throughout this passage is:

“Today”

This is the moment of decision.

Not yesterday. Not someday. Today.

If you hear His voice:

Do not delay

Do not harden your heart

Do not presume upon grace

The wilderness generation presumed—and perished.

Final Exhortation

Examine yourself:

Do I merely , or do I truly ? know about Christrest in Him

Has my heart been changed, or only my behavior?

Am I persevering in faith, or slowly drifting?

Because the difference between true and false conversion is not outward appearance—but a living, enduring faith in Christ.

Closing Scripture

“Today, if you hear his voice, do not harden your hearts.” (Hebrews 3:15, ESV)