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.
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.
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.