How can I know I’m a Christian? 1 John 5

For many who turn to faith in Jesus, there usually comes a day when they ask, “How can I know I’m a Christian?”

Why is that? Well, when I was at school my best subject was maths. I liked it because if you got something right you would usually know. “Prove that x=y2+z” is either right or wrong, and you can see it right in front of you.

But Christian hope of heaven isn’t based on stuff you can do or see or revise for – it’s based on faith. And people have faith in all sorts of stuff.

So: How can you be in any way sure God will accept you?

Or: How can you know you’re even a Christian?

That’s what John has been working out for you in 1 John, and it comes to a head here in chapter 5.

These notes accompany a sermon on YouTube. You can find more in the series in our Sermon Index.

Triple evidence of faith (1-4)

All the way through this letter, John has been weaving ideas together – building them up, showing their interconnectedness. We’ve mentioned them before, but now all 3 evidences of faith in a person are brought together in just a few verses.

How you can know if someone is really a Christian? You’ll see the triple evidence of someone worshipping the Right Lord, doing things in the Right Love, and living out a Right Life.

Right Lord

So read 1 John 5:1.

Here we remember again what we mean by Right Lord.

  • He is Jesus, the Christ / Messiah.
  • Eternally begotten of the Father – existing in eternal union with the Father and the Holy Spirit as one God in three persons.
  • The Son, through whom and for whom everything was made, the Word who was with God and who was God and who took on human flesh, becoming born a human.
  • Who died as a sacrifice for the sins of others, then rose and is glorified forever as he reigns over us all.

The devil is a liar. He spreads his lies.

Anyone who believes Jesus is not God in human flesh has believed a lie. Anyone who denies the eternal “Sonship” of the Son (in eternal submission to the Father) has believed a lie. Anyone who thinks Jesus did not die for others, or did not rise from the dead, or that he wasn’t even sinless, has believed a lie.

A child of God, says John, will trust in the Right Lord, the Jesus of the Bible: Son of God, risen saviour.

Right Love

And, a child of God will have the Right Love. Read 1 John 5:1-2. As a child of God you will love your Father, but in particular you will love his children. We’ve spent time exploring what it means to love one another.

  • The example is Jesus, who gave his life for his brothers and sisters.
  • You’re supposed to think likewise, but at a much more mundane and ordinary level. You don’t have to give up your life, but you should be ready to give up time, or energy, or money, or whatever it takes.

So if you ever ask, “How can I know I’m a Christian?” you need to know your faith is in the Right Lord (Jesus, wholly human and divine, sacrifice and risen saviour), and that you live out a Right Love for God’s people – other Christians. Your theology needs to be true and it needs to be seen, worked out towards other Christians.

Right Life

And so the third evidence of your faith is interconnected with the first two. Read 1 John 5:3.

For you to have confidence that you are a child of God, there should be Right Living in your life. Obedience to God. Certainly that means loving Christians. But more, it’s about a holiness of life, turning from sin in repentance every day. Walking in the light as he is in the light – that is, living out a holiness of life by nature and choice.

Not being forced, grumbling. A slave has to do his master’s business whether he likes it or not. But a loving child wants to delight their Father – his commands are not burdensome, but a delight born out of a loving relationship

So if you’ve ever wondered if you’re actually a Christian, this letter is good news for you. There are three evidences of faith you can look for in your own life:

  • Right Lord – “Am I trusting in the Jesus of the Bible, eternal creator who became human to save me?”
  • Right Love – “Am I doing things out of love for his people – helping, working, encouraging, giving?”
  • Right Life – “Am I working to become more like Jesus, repenting of sin, turning away from compromise?”

But none of these are works that save you, obviously. Read 1 John 5:4-5.

These three evidences in your life spring out of faith in Christ. So now: How can you be sure that what you believe is right?

Triple witness to truth (6-12)

Your confidence as a Christian is partly based on the three evidences in your life, and partly on three witnesses to truth.

Now these verses have puzzled people. The first thing we need to say is that the old King James Bible is based on Greek manuscripts that are largely excellent, but very occasionally not so good. In particular, the KJV isn’t the best translation to read for these verses.

The water

The next thing to say is that the best text is still pretty hard to understand: Read 1 John 5:6.

  • Literally, He is the one coming by water and blood, Jesus Christ, not by water alone, but by water and by blood and the Spirit is a witness since the Spirit is truth.
  • What does he mean, to say that Jesus came by “water and blood”?
  • The NLT spells it out for us in a strongly interpretive translation – but one that is almost certainly correct in meaning.

Jesus came into his ministry by water at his baptism. It was his great commissioning, visited on by the Holy Spirit and spoken to by the voice of the Father from heaven. A witness of the triune God.

So how does that prove anything, or act as any kind of witness?

It was from that point on that he healed the sick, raised the dead, calmed storms, fed huge crowds, taught, rebuked, encouraged.

From his baptism onwards, he was shown to be the Son of God, God of God in human flesh. The water (onwards) testifies who he is. Son of God. There’s no higher authority to turn to.

The blood

Jesus ended that earthly ministry at the cross.

  • He shed blood; he died.
  • He was raised again after 3 days. That earth-shattering, history-changing moment proves him.
  • He is alive! The Father raised him by the power of the Holy Spirit – his resurrection is witness!
  • Jesus’ death is an acceptable sacrifice for sin for you and me; his life demonstrates the full price is paid, and life awaits all who believe. His claims were true.

The Spirit

So his blood testifies too. And then the Holy Spirit confirmed it, as a third witness.

  • The sending of the Holy Spirit into the world, into all believers in Christ, is a demonstration of Jesus’ ascension to heaven, to glory, to reigning power – where he still is.
  • The powerful movement of the church, filled and enabled by the Holy Spirit these 2,000 years, is a demonstration of the reality of his work.
  • The life-changing, transforming power of the Bible, written by men carried along by the Holy Spirit, is witness of the work of Christ going on.

So read 1 John 5:7-9.

The things Jesus did from his commissioning baptism onwards proves it; his death and resurrection prove it; the action of the Holy Spirit in the world, church, and Bible prove it.

  • There is no higher authority.
  • If you choose not to believe this, you reject truth and embrace lies. Read 1 John 5:10.

Human witness is often really impressive, but no-one has yet done what Christ has done. It’s not possible, because only he is the Son of God who came to earth to save you, and is now risen and exalted and worshipped and adored and glorified!

Eternal life

And why does all this matter again? Read 1 John 5:11-12.

Of everything you ever hear in your life, this is the most important.

Of everything you ever hear in your life, this is the most important. You will have eternal life with God, or you won’t. Eternal life is only found by faith in Jesus Christ, that he has taken the punishment you deserve, and that he is willing to forgive you as you turn from sin to him.

Are you really a Christian?

  • The answer to that isn’t in whether you feel it. It’s not about how strong your faith is, or how much you know.
  • Sometimes people come to faith in Jesus, and then when they know a bit more they wonder if they really did come to faith! “Did I get baptised too soon?”
  • But your confidence is in objective truth outside of you. It’s in Jesus, son of God, who died for you. Confirmed in wonders by the Father and Spirit. 

It’s evidenced in your life by your trust in the Right Lord (Jesus, human and divine), a Right Love (for your brothers and sisters in Christ) and Right Living (working towards holiness and light).

But all that then has to be worked outwards from you:

Live truth out (13-21)

John hasn’t written all this as an intellectual exercise. You’re meant to live it out. Read 1 John 5:13-15.

Don’t miss what he says in v13 – he’s giving you the reason for the whole letter.

  • If you are a Christian, and you have doubts over whether you’re the real thing or not, this letter is for you.
  • You’re to rest on the 3 objective witnesses to truth, and then live out your Christian life with 3 evidences of faith.
  • Stop worrying about whether you “feel” like a Christian because then you’re trusting your feelings when you should be trusting Christ and the truth about him the Holy Spirit has revealed.

Equally, if you know you’re not a Christian, John’s letter is blunt: “Whoever does not have the Son does not have life.” You’re still on the road to hell, and to hell you will go unless you turn to Jesus now.

But that’s the positive aspect of v14-15. If you turn to God for forgiveness of your sin, he will delight to hear that prayer and will answer. He will forgive. You will live eternally, a child of God!

And just as you pray for your own sin, pray for others too. Read 1 John 5:16-17.

  • It’s not “judging” someone to discern that they have sinned against God. You’re judging them if you look down on them and condemn them.
  • But John is saying pray for one another, that the Lord would be gracious to us all.

Christ is life

We need to do that because we will all still sin (back to Ch 1). But, as God’s children, he won’t let us go. Read 1 John 5:18-19. As a child of God, your life must look different from the lives of people around you.  The world is under the sway of Satan, but you’re not. The world may oppose you because Satan does, but it can do no lasting harm to you. Eternal life is in Jesus.

And so, as a Christian, truth is revealed to you in Jesus Christ. In Christ you know the true and living God. You live in him; he lives in you. You speak to him and you hear from him.

And to be in fellowship with God in Christ is to taste eternal life, to experience it.

Read 1 John 5:20, slowly. Drink it in!

Small wonder he ends as he does: Read 1 John 5:21.

Literally, Children, keep yourselves from idols.

  • Keep yourself from things that offer pleasure in this life but can’t bring you eternal life.
  • Keep yourself from anything that doesn’t motivate God’s love in you; things that promote self-love.
  • Don’t be robbed of eternal assurance of faith, of truth, of joy, of fellowship with God.
  • Idols are man-made, gods made in our image.

Trust in the objective, glorious truth of God’s identity and the salvation he brings you in his Son (water, blood, Spirit).

Look for objective realities in your own life as you live out this saving truth, day by day, person by person. Remain in Christ.