What If I Am? The Assurance of Faith in Christ

Part 3 of 3 in the Gospel Response Trilogy. Best read after “What If I Don’t?” and “What If I Do?”

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Introduction: From Question to Confidence

You have walked through two hard, necessary questions:

“What if I don’t?” exposed the terror of remaining in Adam—under condemnation, heading toward judgment and eternal hell.

“What if I do?” unveiled the glory of repentance and faith—justification, adoption, union with Christ, and the hundredfold reward of discipleship.

Now comes the question that moves from fear to assurance, from decision to confidence:

“What if I am?” What if I have truly repented and believed? How can I know? And how does that assurance grow and sustain me?

This is not a question of uncertainty about Christ’s sufficiency. It is a question about your own heart: Have I truly been saved? Am I really a child of God?

Scripture does not dodge this question. It invites it. “Examine yourselves, to see whether you are in the faith” [2 Cor 13:5]. The gospel promises assurance to those who truly believe, and the whole New Testament brims with believers who know they are saved.

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Part 1: What Does It Mean to Be “In Christ”?

1. The reality of union with Christ

When you repent and believe, you are not just forgiven from a distance. You are united to Christ. This is the central, transforming reality from which everything else flows.

The apostle Paul says repeatedly:

“It is no longer I who live, but Christ who lives in me; and the life I now live in the flesh I live by faith in the Son of God, who loved me and gave himself for me.” [Gal 2:20]

Union with Christ means:

• You died with Him—your old self, in God’s reckoning, was crucified at Calvary. The dominion of sin has been broken over you.
• You rose with Him—you are alive now with new spiritual life, seated in the heavenly places with Christ. ​
• You live in Him—His life becomes your life; His standing becomes your standing; His future becomes your future.
• This is not mysticism. It is the biblical way of saying: you are no longer spiritually homeless. You are incorporated into Christ’s person, sharing in all that is His—His righteousness, His resurrection, His inheritance. ​

2. The marks of true conversion: fruit-bearing faith

If you are truly in Christ, certain things will begin to appear in your life. Not perfectly. Not immediately in every area. But genuinely.

The Westminster Confession says that believers are “justified by faith in Christ, the righteousness of which faith is imputed unto them.” But it also says that faith, being a living faith, is “operative by love.” In other words, real faith works. It produces fruit. ​

Jesus said, “By their fruits you will recognize them” [Matt 7:16]. What are those fruits?

Mortification of sin: You are no longer at peace with sin. Things that once felt normal now disturb you. You grieve over specific sins, confess them, and seek to put them to death—not because you are trying to earn God’s favor, but because your heart has been changed. ​

Vivification in righteousness: Where sin dies, obedience sprouts. You find yourself drawn to God’s Word. Prayer becomes real. Love for other believers grows. Service to the needy feels natural.

Love for God and His people: “By this we know that we love the children of God, when we love God and obey his commandments.” [1 John 5:2] Do you find yourself loving Christ? Does His glory matter to you? Do you love His people, even when it costs?

Perseverance: You stumble and fall—sometimes into real, grievous sin—but you cannot make peace with it. You confess, you repent, you rise again. The pattern of your life is not perpetual sin; it is sin-repentance-forgiveness-growth. ​

These fruits are not evidence that you are earning salvation. They are evidence that you have received it. They are how you can say, “I am beginning to believe that I truly am in Christ.”

3. The work of the Holy Spirit: witness and seal

But how can you be sure? You cannot peer into your own heart perfectly. You cannot grade your own obedience fairly. So God gives a deeper assurance: the witness of the Holy Spirit.

Romans 8:16 says: “The Spirit himself bears witness with our spirit that we are children of God.”

This is not an audible voice or an eerie feeling. It is the Spirit’s quiet, steadfast testimony working alongside your own reflection on God’s promises. When you read, “As many as received him, to them gave he power to become the sons of God” [John 1:12], and you say, “Yes, I have received Him,” the Spirit witnesses: That is you. You are a child of God.

The Shorter Catechism puts it thus: Assurance of salvation “is not a bare conjectural persuasion, but an infallible assurance of faith, founded upon the divine truth of the promises of salvation, the inward testimony of the Holy Ghost, and thine own conscientious endeavor after a true and universal obedience.”

In other words, assurance rests on:

• God’s promises: “Whoever believes in the Son has eternal life” [John 3:36]. God cannot lie.
• The Spirit’s testimony: An inward work confirming those promises are for you.
• Your own conscious striving for obedience: Not perfection, but a real, observable turning from sin and toward holiness.

When these three converge, you can say with confidence: “I am in Christ.”

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Part 2: The Doctrine of Perseverance—God’s Promise to Keep You

One of the deepest threats to assurance is the fear: But what if I fall away? What if I lose my salvation?

Reformed theology offers a radical answer: You cannot lose it, because God has promised to keep you to the end. ​

4. Perseverance: your security in His hands

The Westminster Confession teaches what it calls the Perseverance of the Saints:

Those whom God hath accepted in His Beloved… can neither totally nor finally fall away from the state of grace; but shall certainly persevere therein to the end, and be eternally saved, because persevering in their union and communion with Christ, and by His Spirit dwelling in them, they are kept by His power through faith unto salvation.

This doctrine does not mean:

• You will not sin. David fell into adultery and murder. Peter denied Christ three times.
• You will not struggle. Believers face seasons of doubt, darkness, and dry spiritual seasons.
• You will not need to be disciplined. God sometimes chastens His children for their good. [Heb 12:5–11]

But it means:

• God has not left your salvation in your hands. You did not save yourself; you cannot unsave yourself. Your standing rests on Christ’s work, not your performance. ​
• The same grace that made you a believer will keep you believing. Election, effectual calling, regeneration, faith, justification—all of it flows from God’s unchanging decree and covenant.
• The Holy Spirit abides in you. His indwelling is not conditional on your perfect behavior; it is a seal and guarantee of your future inheritance. [Eph 1:13–14]

Jesus Himself said:

“My sheep hear my voice, and I know them, and they follow me. I give them eternal life, and they will never perish, and no one will snatch them out of my hand. My Father, who has given them to me, is greater than all, and no one is able to snatch them out of the Father’s hand.” [John 10:27–29]

Not might perish. Will never perish. Not might be snatched. No one will snatch them.

5. How does God keep you? Through faith

Perseverance is not passive. God does not save you and then leave you idle. Rather, He keeps you by His power through faith.

This means:

• God sustains your faith—even when you feel like your faith is weak, even when doubt assails, the root of believing remains.
• You do not work to maintain your salvation; you rest in Christ and draw on His strength. “I can do all things through Christ who strengthens me” [Phil 4:13].
• Your part is to abide—to remain in union with Christ through prayer, the Word, the sacraments, and the fellowship of saints. His part is to keep you secure.

One Puritan said it beautifully: “Perseverance is both God’s gift and your responsibility—God guarantees the outcome, but does not remove your effort.” ​

So when you ask, “What if I am truly saved, but I stumble into serious sin?”, Scripture’s answer is not, “Then you were never saved.” It is, “God will chasten you, lead you to repentance, and restore you, because He will not lose you.”

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Part 3: Examining Yourself—Growing in Assurance

6. Self-examination is a grace, not a burden

The call to examine yourself can feel burdensome: Am I good enough? Am I holy enough? Do I love God enough? But Scripture presents it as a grace—a way to grow confident rather than fearful.

Paul says:

“Examine yourselves, to see whether you are in the faith. Test yourselves. Do you not realize that Christ Jesus is in you?—unless, of course, you fail the test!” [2 Cor 13:5]

The point is not to spiral into despair. The point is to soberly ask: Do the marks of a believer appear in my life? Is Christ truly in me?

7. Tests of true faith

Ask yourself these questions:

Test 1: Do I mourn my sin?

“Blessed are those who mourn, for they will be comforted” [Matt 5:4]. Do you grieve over your sin—not just fear punishment, but feel sorrow that you have dishonored God? A person who has truly met the holy God cannot make peace with sin anymore. ​

Test 2: Do I hunger for righteousness?

“Blessed are those who hunger and thirst for righteousness” [Matt 5:6]. Not perfection, but a real longing to be holy, to obey, to please God? Do you want to grow in grace?

Test 3: Do I love God?

“We love him because he first loved us” [1 John 4:19]. Is there a genuine affection for God? Does His glory matter to you? Not that you always feel it, but is Christ precious to you in your heart? ​

Test 4: Do I love God’s people?

“By this we know that we have passed out of death into life, because we love the brothers” [1 John 3:14]. Do you care for other believers? Are you part of a church family? Is the growth and holiness of Christ’s people important to you?

Test 5: Do I keep His commandments?

“And by this we know that we have come to know him, if we obey his commandments” [1 John 2:3]. This does not mean sinless perfection. It means: is there a real, observable pattern of obedience? Are you working to put to death sin and cultivate holiness?

Test 6: Do I believe Jesus is the Christ?

“Everyone who believes that Jesus is the Christ has been born of God” [1 John 5:1]. Saving faith has a specific object: Jesus. Do you truly believe He is who He claims? Do you trust Him as your Savior and Lord?

If these marks are growing in your life—however small, however mixed with failure—then you have strong grounds for assurance. You can say with confidence: “I am in Christ.”

8. What if I find these marks lacking?

If you examine yourself and feel the marks are largely absent—you do not grieve sin, you do not hunger for righteousness, you feel no real love for God or His people—then the gospel does not say, “Try harder.” It says, “Come to Christ as you are.”

The way to assurance is not self-improvement. It is repentance and faith. If you realize you have never truly turned from sin and trusted Christ, do so now. Confess your need. Ask Christ to make you a new creation. Trust Him with your whole life.

And if you have truly come to Christ but are in a season of spiritual darkness or struggle, the answer is still not to improve yourself. It is to remember the promises, to cry out to God, to get into His Word and His church, and to wait for the Spirit’s renewed witness. ​

Assurance is not arrogance. It is humble trust in God’s promises and patient reliance on His kept oath.

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Part 4: Growing in Assurance Over a Lifetime

9. Assurance is not static; it grows

When you are first converted, assurance may feel like a blazing fire—the relief and joy of being forgiven, the freedom of a new life, the wonder of knowing Christ.

Over time, that initial fire may bank into glowing coals. The emotional intensity fades. Life gets complicated. Trials come. Doubt whispers. In those moments, assurance can feel fragile.

But here is the promise: assurance grows through trials. As God proves faithful again and again, as you witness His keeping power in dark seasons, as you see how He works all things for good in your life, assurance deepens from emotion to settled conviction.

The Westminster Confession says saving faith “is increased and strengthened” through the ordinary means of grace: God’s Word, the sacraments (Communion), and prayer. It also grows through affliction, as you find Christ faithful when the storm comes.

10. What you can know for certain

So “What if I am?” can be answered this way:

If you have repented and believed, then:

• We are justified — your sins are paid for, our righteousness is complete in Christ, we will never be condemned.
• We are adopted — God is our Father, we are His child, we have an inheritance beyond measure.
• You are indwelt by the Spirit — He is your Helper, Comforter, and Guide. ​
• You are kept by God’s power — you cannot lose your salvation because it does not rest on you; it rests on Christ.
• You are being sanctified—God is actively working in you to make you holy, and He will finish the work He started in you. ​
• You will persevere to the end—not because you are strong, but because God is faithful.
• You will be glorified—one day you will see Jesus face to face and be made perfect.

These are not feelings or guesses. These are promises. And God cannot lie.

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Part 5: The Trilogy Complete—From Question to Confidence

Bring together all three questions:

“What if I don’t?” → The dread of remaining condemned, heading toward judgment and eternal separation from God. ​

“What if I do?” → The wonder of repentance and faith, of gaining Christ, of becoming a new creation, of a life of discipleship with real cost and real reward.

“What if I am?” → The settled assurance that, having believed, you are secure forever in Christ, kept by God’s power, and bound for glory. ​

The trilogy moves you from:

• Terror (facing judgment)
• Through Decision (turning to Christ)
• Into Confidence (assured in God’s keeping)

11. A final invitation

If you are reading this and you have never truly asked, much less answered, “What if I do?”, then this is your invitation:

The gospel is not conditional. It is not for people who have cleaned up their lives or achieved some spiritual standard. It is for the weary, the guilty, the lost, the broken.

Jesus said, “Come to me, all who are weary and heavy laden, and I will give you rest” [Matt 11:28]. He did not say, “Come when you are good enough.” He said, Come now.

Ask yourself the hard questions: Do I believe Jesus died and rose for me? Do I want to turn from sin and follow Him? If the answer is yes—even with doubt and weakness mixed in—then do it. Repent. Believe. Come to Christ.

And if you have already come, if you have already repented and believed, then let these words settle into your heart:

You are His. You are kept. You are bound for glory. You can say with confidence: “I am in Christ.”

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Conclusion: The Assurance That Sustains

The end of “What if I am?” is not a question mark but an exclamation point. Not uncertainty, but settled joy.

The apostle John wrote: “I have written these things to you who believe in the name of the Son of God, that you may know that you have eternal life” [1 John 5:13]. Not that you might guess. Not that you might hope. But that you may know.

That is the promise of the gospel. Not a fearful wondering through life, but a confident resting in Christ’s promises and God’s faithfulness.

If you are in Christ, you are secure, you are loved, you are destined for glory. What if you are? Then everything changes. And nothing can ever take it away.

Thank you for reading along. I appreciate you all more thank you know.

Godspeed & God bless.