You can know you have eternal life.

These things I have written… so that you may know that you have eternal life.

Four things are worth carrying with you from this walkthrough. First, faith needs an object — it isn't believing hard enough that saves, it's who you're trusting. Give people something real to believe: He is the Son of God (John 20:31), He died for our sins — behold, the Lamb of God who takes away the sin of the world (John 1:29) — and He rose again (John 20).

Second, the invitation is to believe in Christ as Savior — nothing more mysterious than that. Not "ask Jesus into your heart." Not "give your life to Jesus." Not "surrender to Him as Lord." Those phrases aren't Scripture's own vocabulary for receiving eternal life, and they tend to confuse people about what's actually required, making a simple gift sound like a negotiation.

Third, assurance rests on the Word, not on feelings, performance, or a memorable moment. 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). Not hope. Not guess. Know. There may be other supporting evidences along the way, but God's own testimony is sufficient assurance, and anything else is a distant second.

Fourth, keep the gospel free. To John, the sin that condemns is unbelief, and the cure for unbelief is belief — not a better performance, not more sincerity, but belief in what Christ has already finished. If you have believed in Jesus — trusted His promise to give you eternal life — that settles it. Not because your faith was strong enough, but because His promise was.