1 John overview — how to know you really have Jesus
Dillon McCurdy · September 13, 2026 · 6 min read
Through 1 John, part 1 · Introduction
First John is one of the most encouraging and convicting books in the Bible, often in the same paragraph. It's short, it's plain, and it keeps circling back to one question: how do you know you really have Jesus? Before we walk through it, here's who wrote it and why.
Who John was
John was one of the Twelve and the brother of James. He was a fisherman with James, Peter, and Andrew. Jesus nicknamed the two brothers "sons of thunder." He was one of the three closest to Jesus — you'll find him sitting next to Jesus at the Last Supper — and he calls himself "the disciple Jesus loved." He was the only disciple at the cross, and from the cross Jesus put His mother in John's care. Paul called him a pillar of the church. He wrote more Scripture than any other of the Twelve — a Gospel, three letters, and Revelation. Tradition says he was the only apostle not martyred; he ministered in Ephesus, trained men like Polycarp and Ignatius, and was exiled to Patmos.
Who he wrote to, and why
We don't know the exact audience, but it's clearly believers. And John tells us why he's writing, over and over. "So that you may also have fellowship with us" (1:3). "So that our joy may be complete" (1:4). "So that you may not sin" (2:1). "Concerning those who are trying to deceive you" (2:26). And the one that sums up the letter: "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" (5:13).
The big ideas
How to know if you really have Jesus. John exposes the counterfeit and gives confidence to the sincere. And then — Jesus, Jesus, Jesus. John loved Jesus. Oh, to have the love of John, the zeal of Peter, and the persistence of Paul.
Chapter by chapter: chapter 1 is the eternality of Christ, the message of Christ, and the deliverance of Christ. Chapter 2 is how to deal with personal sin, how to know you know Him, how to know you don't, why not to love the world, and how to spot deception. Chapter 3 is the love of God toward us and the righteousness of God's children. Chapter 4 is avoiding error and loving one another. Chapter 5 is love for others, eternal life through Jesus, and growing your relationship with God.
Three words
Count them and you'll see the shape of the letter. Love — 35 times. Know — 33 times. Because — 27 times. John tells us to know the love of God, to show love toward others, and he gives us the reason — the "because" — for both.
The key verse: "Dear friends, if God loved us in this way, we also must love one another" (1 John 4:11).
Something to expect
Romans shows us God as Judge and our legal standing before Him. First John shows us God as Father and our fellowship with Him. If you've been through Romans, you'll notice the difference right away — Paul is arguing a case; John is talking to his children. Keep that in mind, because a lot of the hard sayings in this letter make sense once you remember they're written by a father who wants his kids to be sure.
Two people are going to read through this letter with us. One of them is already sure and just wants to be surer. The other has sat in church for years and has never once known whether any of it was actually his. If that's you, John wrote the whole thing with you in mind, so don't wait five parts to settle it. Jesus, the Son of God, died for your sins and God raised Him, and everyone who calls on Him is saved. Not everyone who tries hard. Everyone who calls. Do that today and you'll read the rest of this letter as a child instead of a visitor.
If you're already His, here's the week's work: read all five chapters in one sitting. It takes about fifteen minutes. Mark every "because" you come across — there are twenty-seven of them in there. John never asks you to feel your way into assurance. He hands you reasons. Go collect them.
Through 1 John: Part 1 · Part 2 →