On Assurance in the Christian Faith


Comfort and assurance in faith can seem elusive. So much so, the Apostle John wrote in his first epistle, “I have written these things to you who believe in the name of the Son of God so that you may know that you have eternal life” (1 John 5:13). He wrote to comfort and assure fellow believers. People who already had faith in Jesus as the Christ. John’s hearers were shaken in their faith when some people left their church claiming other “truths” about the Son of God. This is not unlike us today when faced with competing truth claims. The apostle writes to us too!

Assurance for the Christian comes not from within; from one’s inner power or strength to believe or from the amount of faith one has. Like salvation, it comes “extra nos” — outside of ourselves. Our assurance doesn’t come from some inner ethereal, subjective feeling. Rather, it comes from without, from concrete verifiable reality.

Our assurance comes to us on the lips of another. Namely, the Spirit of God and His confession. He confesses that Jesus Christ, our advocate before the Father for eternal life, came not in mere appearance of humanity, but in real, human flesh and blood.

John says the Spirit testifies that Jesus Christ came “not with water only but with the water and the blood” (1 John 5:6). By this the apostle combats the idea that God’s self-revelation and salvation are merely spiritual events. They’re also physical. God grounds the revelation of Himself and the salvation won for us by His Son in verifiable reality.

John recounts in his Gospel how he witnessed proof of Jesus’ physical death on the cross.

“Instead, one of the soldiers pierced his side with a spear, and at once blood and water came out. He who saw this has testified so that you also may believe. His testimony is true, and he knows that he tells the truth” (John 19:34–35).

If Jesus was a spiritual being disguised as a human, this fleshly proof of death could not have happened. John ties our faith, and our assurance of eternal life, to the historical event of Jesus’ death and to His subsequent resurrection. Both verifiable events with sufficient witness.

John also writes that the water and blood testify together with the Spirit. The Spirit, the water, and the blood testify that the life Jesus gave up on the cross is now ours. In this way, John points directly to our baptism. There the blood of Christ, shed in history, comes directly to us and cleanses us of all our sin

The waters of baptism are stained with the blood of Christ. There the Spirit of God creates faith in us. He unites us to Christ’s death and resurrection and to the forgiveness, salvation, and life they bring. All of us “who have been baptized into Christ Jesus were baptized into his death” and resurrection. (Romans 6:3–5).

John assures us further. “Everyone who believes that Jesus is the Christ has been born of God…” and “whatever is born of God conquers the world. And this is the victory that conquers the world, our faith” (1 John 5:1, 4). We are born of God. Not by our own power or will, but by the power of the Spirit in the Word of God. In baptism, which is God’s Word attached to physical water, the Spirit’s power poured out on us creates faith in us. It comes to us extra nos — outside of ourselves. We did not choose Him; He chose us (John 15:16).

The faith we receive comes as an unmerited gift from God. And, this gifted faith is not blind. The object of our faith is Jesus Christ, the Son of God who entered time and space. He came in human flesh to live a life free from sin that we could not live. He died a physical death to pay for real sins for which we could not pay. He rose a bodily resurrection to defeat a death we could not overcome.

His entrance into verifiable history, our objective reality, gives grounding to our assurance. It really happened. It’s really finished. Finished for you.

Kyle is many things: husband, professional church worker, theological thinker and writer, musician, introvert, reader, tea and coffee, craft beer consumer, chronic over-thinker, helplessly hipster, Floridian living in Texas, roller derby fan, and the founding editor of The Gospel Economist, a group of writers and contributors that seek the story of Jesus Christ and his payment for our sin in our everyday lives.

He is also a sinner and justified, simultaneously. He is a sinner by his own thoughts, words, and actions and, at the same time, justified by grace through faith in the work of Jesus Christ.