1 John 5:13-21
There is no shortage of uncertainty in the world around us. Headlines change by the hour. Opinions are presented as facts and lies are presented as truth. People wonder what tomorrow will bring, whom they can trust, and even whether there is such a thing as truth anymore.
Christians see the same world everyone else sees. We experience the same difficulties, hear the same troubling news, face the same temptations, and encounter circumstances beyond our control. Yet Christians do not have to live as uncertain people in an uncertain world.
Why can that be said?
Because the Christian life is not built upon what we guess. It rests upon what God has made known.
That is where John brings us at the conclusion of his first letter. In 1 John 5:13–21, John repeatedly uses the language of knowing. He does not say, “we think,” “we hope,” or “we suppose.” Again and again, John tells believers what we know.
This is especially significant because of everything John has addressed throughout the letter. He has given us tests involving truth, obedience, love, righteousness, and discernment. He has warned about false teachers and antichrists. He has confronted sin and challenged us to love one another. But his purpose was never to leave genuine Christians frightened and constantly wondering whether they really belong to Christ. John has been leading the faithful believer, us, towards assurance.
First, we can know that we have eternal life.
“These things I have written 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).
Christian assurance is not saying, “I have been good enough.” It is saying, “Jesus Christ is enough.” Our assurance does not rest in what we have accomplished for Christ, but in what Christ has accomplished for us. Like David in Psalm 23:6, who confidently looked forward to dwelling “in the house of the LORD forever,” the believer can know where the Good Shepherd is taking His people.
Second, we can know that God hears us when we pray.
John writes that “if we ask anything according to His will, He hears us” (1 John 5:14). That qualification, “according to His will,” is important. Biblical confidence in prayer is not believing that God must do whatever we ask. It is knowing that God hears what we ask and trusting what He decides.
Look how Psalm 34:15 says, “The eyes of the LORD are toward the righteous and His ears are open to their cry.” We pray because our Father hears us. As prayer matures, it also moves beyond us and our personal desires. John specifically speaks about praying for a brother caught in sin. Prayer becomes one of the ways God’s people carry one another before Him.
Confidence in prayer is not confidence that God will follow our will, but confidence that we can trust His.
Third, we can know that sin does not own us.
John is not teaching sinless perfection. Earlier he wrote, “If we say that we have no sin, we are deceiving ourselves” (1 John 1:8). Christians still struggle with sin, we still confess sin, and we still need forgiveness.
But sin no longer owns the person who has been born of God.
John tells us that Christ keeps His people and “the evil one does not touch him” (1 John 5:18). Psalm 37 describes the same security: even when the righteous person falls, “he will not be hurled headlong, because the LORD is the One who holds his hand” (Psalm 37:24).
Our victory is not that we never fall; our confidence is that Christ never lets us go.
Fourth, we can know that we belong to God.
“We know that we are of God” (1 John 5:19).
Throughout his letter, John has contrasted light and darkness, truth and lies, love and hatred, Christ and antichrist, the children of God and the children of the devil. Now, near the end, he does not leave believers in a place of uncertainty. We can know, with great confidence, that we are His.
The Psalmist says, “Know that the LORD Himself is God; it is He who has made us, and not we ourselves; we are His people and the sheep of His pasture” (Psalm 100:3).
What security there is in those words: We are His.
The greatest security a Christian possesses is not knowing what tomorrow holds but knowing the God who holds us.
Finally, we can know the One who is true.
John writes that “the Son of God has come, and has given us understanding so that we may know Him who is true” (1 John 5:20).
The truth of God ultimately brings us to a Person: Jesus Christ.
God does not merely tell the truth occasionally. Truth belongs to His very character. “The sum of Your word is truth,” Psalm 119:160 declares. Jesus has come so that we can know the One who is true, belong to the One who is true, and have eternal life in Him.
That makes John’s final sentence especially powerful:
“Little children, guard yourselves from idols” (1 John 5:21).
Once we know the One who is true, why would we exchange Him for something else? Why would we trade the truth for a lie?
Tomorrow, the world will still be uncertain. There will still be troubling headlines. There will still be lies presented as truth. There will still be temptation, evil, and circumstances beyond our control. But none of those things change what God’s children know.
We know eternal life is ours in Christ. We know our Father hears us. We know sin does not own us. We know we belong to God. Above everything else, we know the One who is true.
We were not created to know everything. We were created to know Jesus.
So, we do not have to walk into the world consumed by its uncertainty. We can walk into it knowing who we are.
We are children of God. We belong to Him and He will never leave us nor forsake us.
Walk into the world knowing to Whom you belong.