How can a believer have assurance of salvation?

TL;DR:

A believer can have assurance of salvation on the basis of Christ’s finished work and the indwelling of the Holy Spirit. Assurance of salvation also comes by repentance and living for God even when we struggle with sin or doubt our salvation.

what does the bible say?

Many believers struggle with assurance of salvation, especially when they have sinned, lost passion for Christ, or go through a spiritually dry or difficult season. But, the Bible is clear that a Christian cannot lose their salvation. Our salvation is dependent on Christ’s work on our behalf, not anything we do (Ephesians 2:8–9; Titus 3:5).. So, when we trust in Him, repenting of sin, submitting and surrendering to Him, we are saved. Further, the Holy Spirit indwells believers at the moment of salvation, and He will not leave us (Ephesians 1:13-14; Romans 8:9, 16). Salvation will be followed by holy affections that consistently manifest in a new spiritual life (2 Corinthians 5:17). Though we may struggle or fall into sin, the mark of the true believer is that they repent and continue living for God. Our assurance is based on who God is, what He has done, and the transformed life He makes in us.

from the old testament

Assurance of salvation is rooted in God’s covenant faithfulness—He saves, sustains, and keeps His people (Isaiah 43:1; Psalm 23:6; Psalm 121:7–8). Believers can trust that even when they stumble, God’s promises never fail.

from the new testament

The Bible commands Christians to ensure they are truly in the faith, that they aren't self-deceived into thinking they're truly saved when they're not. Paul says, "Examine yourselves, to see whether you are in the faith. Test yourselves. Or do you not realize this about yourselves, that Jesus Christ is in you?—unless indeed you fail to meet the test!" (2 Corinthians 13:5).
Peter also calls us to ensure our salvation: "Therefore, brothers, be all the more diligent to confirm your calling and election, for if you practice these qualities you will never fall" (2 Peter 1:10).
God wants us to have assurance of salvation: "I write 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).
We are saved not by our own efforts, but by God’s grace through faith in Christ (Ephesians 2:8–9; Titus 3:5). Jesus’ death on the cross and resurrection saves us; our responsibility is to accept and trust in that.
Jesus promises that no one can snatch His sheep from His hand, and He will raise them up on the last day (John 10:27–29, 6:39). This means our salvation is secure and kept in Christ.
At the moment of salvation, the Holy Spirit indwells believers and is the guarantee of our inheritance. The Holy Spirit will never depart believers, confirming that our salvation is secure (Ephesians 1:13-14; Romans 8:9, 16).
Assurance comes through Christ’s finished work and the Spirit’s indwelling—those who trust in Him are secure forever (John 10:28–29; Romans 8:38–39; Ephesians 1:13–14). Salvation produces transformation into Christlikeness (Romans 8:29; 2 Corinthians 3:18) and the fruit of the Spirit (Galatians 5:22–23) as evidence of God’s keeping power (Philippians 1:6; Jude 1:24).

implications for today

True Christians cannot lose their salvation. So what makes a true Christian? Christians in every generation have wrestled with what marks real saving faith, which is an important question related to having assurance of salvation. During the First Great Awakening (1725–1750), thousands claimed to be converted under the preaching of Jonathan Edwards and George Whitefield. Yet, just a few years later, critics dismissed the movement as emotional hype because so many “converts” showed no evidence of changed lives. In response, Edwards wrote A Treatise Concerning Religious Affections, arguing that true Christianity cannot be measured by outward actions alone but by inward transformation.

Edwards opened his work with a piercing question: What are the distinguishing marks of those who are in favor with God and entitled to His eternal rewards? That question still matters today, when spiritual activity—church attendance, baptism, or even saying the right words—can be mistaken for authentic faith. The Bible is clear: salvation comes through repentance, faith in Jesus Christ (Joel 2:32; Acts 16:31), and new birth by the Spirit (John 3:3, 5).

But how can we tell that this new birth is real? Two marks stand out: new affections and new fruit. Edwards observed, “True religion, in great part, consists in holy affections.” A believer receives a new appetite, a hunger for God and His Word (2 Corinthians 5:17). Those inward affections naturally express themselves in outward fruit, as James explains: faith without works is dead (James 2:14). Or in Edwards’ words, just as motion proves physical life, holy motion proves spiritual life. Jesus put it simply: “The tree is known by its fruit” (Matthew 12:33).

This doesn’t mean Christians never struggle with sin or that they’re always passionately pursuing Christ. Paul himself described his ongoing battle in Romans 7. The difference is that genuine believers cannot remain comfortable in sin or dismiss it as harmless. A true Christian will hunger for God and not remain in a dry, desolate place spiritually. True saving faith repents, keeps turning toward God, and bears fruit over time.

The question is still urgent: Is our faith producing godly affections and holy fruit? Assurance of salvation doesn’t come from relying on a past decision, but from seeing the Spirit’s ongoing work in our lives. Real saving faith is alive, moving us toward Christ, and marked by a growing love for God.

understand

Believers can have assurance of salvation because of Christ’s finished work on the cross.
Believers’ salvation is assured because of the indwelling Spirit who never departs us.
Believers can be assured of salvation because the Holy Spirit helps us repent and live for God, not staying in our sinful or doubting state.

reflect

When you struggle with sin or doubt, why is it important to remind yourself that your salvation rests on Christ’s finished work and not your performance?
Where do you see evidence of the Holy Spirit’s transforming work—new desires, repentance, and spiritual fruit—in your life?
How do you rely on the truth of God’s promises rather than your feelings to assure you of your salvation?

engage

How can we encourage other believers to remember God’s work in salvation when doubts about salvation arise?
What are some ways we can discern genuine saving faith in our lives and in the life of those who profess to be believers?
Why is it important to distinguish between temporary struggles with sin and a lifestyle of unrepentant sin when thinking about assurance of salvation? What can we do to grow in faith and assurance during these times?