How to Know That You Know God

1 John 2:3-11

And by this we know that we have come to know him if we keep his commandments. Whoever says “I know him” but does not keep his commandments is a liar, and the truth is not in him, but whoever keeps his word, in him truly the love of God is perfected. By this we know that we are in him. Whoever says he abides in him ought to walk in the same way in which he walked.

Beloved, I am writing you no new commandment, but an old commandment that you had from the beginning. The old commandment is the word that you have heard. At the same time, it is a new commandment that I am writing to you, which is true in him and in you, because the darkness is passing away and the true light is already shining. Whoever says he is in the light and hates his brother is still in darkness. Whoever loves his brother abides in the light, and in him there is no cause for stumbling. Whoever hates his brother is in the darkness and walks in the darkness, and does not know where he is going, because the darkness has blinded his eyes.

The Purpose of Joy in Christ

John writes this epistle so that our joy may be full and complete. The message of Jesus Christ is that those in fellowship with God do not have fellowship with sin. People who have fellowship with God do not continue to practice sin. You have joy by being a Christian. As John describes the marks of a Christian, you can examine your own life to see if you are a genuine Christian by the way you live.

Many say all you need is faith, with no focus on what you do. Faith alone saves, but saving faith is never alone. It is always accompanied by a lifestyle that demonstrates faith—a change in what you do because you are saved. This change comes from understanding that Jesus is light, God is light, and in Christ, your life is completely exposed.

Light exposes. As 1 John 1:9 says, if we confess our sins, God is faithful and just to forgive us. A Christian walks in the light, with sins exposed, resting in forgiveness. It's not just putting sins out there in shame, but trusting Jesus to save and forgive, which motivates you not to sin. John writes so that you don't sin, but if you do, you have an advocate: Jesus Christ the righteous, the propitiation for your sins.

The "Get Out of Jail Free" Illustration

A Christian does not hide sin but has a life fully exposed, trusting in Christ's forgiveness. Imagine being caught by police for a crime—you'd deny it to avoid punishment. Or your parents confront you about breaking something—you'd lie or blame a sibling to escape trouble.

But suppose your parents gave you a "get out of jail free" card, redeemable for any offense. When confronted about punching a hole in the wall with a baseball bat, you'd confess freely because punishment is covered. Yet this doesn't mean you go sin more—like kicking the neighbor's cat or throwing rocks. John writes against that: knowing Christ enables you to stop sinning, not perfectly, but as motivation.

Propitiation means Jesus took God's wrath meant for you. Imagine your innocent brother crucified in your place—tortured, nailed to a cross, dying in agony so you're forgiven for the hole in the wall. Anyone with a heart softened by God would not celebrate or sin more. Jesus, sinless, became your brother, bearing every sin—past, present, future—under God's wrath. If knowing this makes you want to sin freely, you have not truly received Christ.

Marks of Knowing God: Obedience

By this we know that we have come to know him: if we keep his commandments. Whoever says, “I know him,” but does not keep his commandments is a liar, and the truth is not in him. But whoever keeps his word, in him truly the love of God is perfected.

John continues radically: you can tell if someone is a Christian, even yourself. Examine your calling and election. The world judges by feelings, but John says know by obedience. Those who abide in Christ obey him.

It's possible to know that you know God—not as a hobby or decision without reality, but genuinely. Test by whether your life matches God's word. Do you keep his commandments?

Keeping commandments means keeping his word, where the love of God is perfected. It involves the gospel, repentance, exposed lives, love—not hating your brother. Jesus summarized commandments as loving God and neighbor. This is an old commandment from the beginning, yet new in Christ, as darkness passes and light shines.

A Christian life shows fruits of the Spirit: love, joy, peace, patience, kindness, goodness, gentleness, self-control. They devote themselves to apostles' teaching, the word—actively opening it to love God and others. Saying you love God means doing it.

Walking as Jesus Walked

Whoever says he abides in him ought to walk in the same way in which he walked. Christians—little Christs—should live like Jesus. How much do you pray like Jesus? Care for others like Jesus, even pouring common grace on non-believers?

Abide in Christ by not hating, loving your brother. In him, there is no cause for stumbling—not just from hate, but sin in general. Your attitude toward others influences your sin. Obeying "love your neighbor" removes stumbling blocks.

Christians keep God's commandments: love God, love neighbor, obey Jesus' words in Scripture. That's how you know if you know God.