A Study of 1 John 1:1–4
If someone asked you to describe Jesus in one word or one phrase, what would you say?
That question may seem simple, but how we answer it reveals what we truly believe about Him. Throughout history people have described Jesus in many different ways—a great teacher, a prophet, a revolutionary, a moral example, or even simply a good man. Yet John opens his first letter by showing that none of those descriptions are enough. Jesus is far more than a religious figure. He is the eternal Son of God who became man so that sinners could have fellowship with God.
John writes this letter because right belief about Jesus produces right living. Throughout the book he continually returns to three foundational marks of genuine Christianity:
- Right belief in Jesus (Truth)
- Right obedience to God’s commands (Obedience)
- Right love for one another (Love)
These themes are woven throughout the letter, but John also tells us exactly why he is writing.
1 John 1:4 — “…that our joy may be complete.”
1 John 2:1 — “…so that you may not sin.”
1 John 2:26 — “…about those who are trying to deceive you.”
1 John 5:13 — “…that you may know that you have eternal life.”
John desires joyful believers, holy believers, discerning believers, and assured believers. All four purposes begin with one foundational truth: knowing the real Jesus.
The Eternal Son Became Man
John begins his letter with remarkable words:
“That which was from the beginning, which we have heard, which we have seen with our eyes, which we looked upon and have touched with our hands, concerning the Word of life…” (1 John 1:1)
Immediately John presents two essential truths about Christ.
Jesus Is Fully Divine
John describes Jesus as the One who was “from the beginning” and as “the eternal life” who was with the Father. Christ did not begin at Bethlehem. He has always existed.
This echoes Jesus’ own words:
“Before Abraham was, I am.” (John 8:58)
Jesus deliberately connected Himself with the divine name God revealed to Moses:
“I AM WHO I AM.” (Exodus 3:14)
John leaves no room for misunderstanding. Jesus is not merely a messenger from God. He is God the Son, eternal with the Father.
Jesus Is Fully Human
Just as strongly, John insists that Jesus truly became man.
The apostles heard Him.
They saw Him.
They examined Him closely.
They touched Him with their own hands.
John was not repeating stories he had heard from others. He was an eyewitness. He walked with Jesus, listened to His teaching, watched His miracles, and after the resurrection even touched His physical body.
Christianity is not built upon religious speculation. It is grounded in historical reality.
Why John Emphasizes Christ’s Humanity
John’s emphasis becomes even more significant when we understand the false teaching threatening the early church.
Toward the end of the first century a philosophy known as Gnosticism began spreading throughout the churches. The word comes from the Greek word gnosis, meaning “knowledge.” Gnosticism blended pagan mysticism with Greek philosophy and rested upon two central beliefs.
First, it claimed that salvation came through secret knowledge available only to a select few.
Second, it taught that all matter was evil while only the spiritual realm was good. If the body was evil but the spirit was good, then serious errors naturally followed.
Some responded through extreme asceticism, believing they should punish and deny their bodies in order to become more spiritual.
Others went to the opposite extreme of licentiousness, arguing that because only the spirit mattered, what they did with their bodies was irrelevant. Morality no longer mattered. Sin supposedly had no spiritual consequences.
Although few people today call themselves Gnostics, this way of thinking is still very much alive. Many continue separating spirituality from obedience, claiming to know God while living however they please.
John wrote to expose these dangerous ideas.
False Teaching Always Produces a False Christ
The greatest danger of Gnosticism was not merely its view of the human body—it distorted the identity of Jesus Christ.
One form became known as Docetism. Since matter was considered evil, its followers concluded that Jesus could not have possessed a real physical body. He only appeared to be human.
John’s opening words directly confront that error.
“We heard Him.”
“We saw Him.”
“We touched Him.”
John is essentially saying, “I was there. His body was real. He truly became flesh.”
Another false teacher named Cerinthus took a different approach. He accepted Jesus’ humanity but denied His deity. According to his teaching, Jesus was merely an ordinary man until the Spirit came upon Him at His baptism. Then, before the crucifixion, the divine Spirit supposedly departed, leaving only the human Jesus to die.
But if Jesus died only as a man, the gospel collapses.
A mere man cannot bear the sins of the world. Only the God-man could serve as our substitute.
These early heresies denied two essential truths: the incarnation and the substitutionary atonement. Those same denials continue today under different names and different systems of belief. Any teaching that rejects Jesus as God in the flesh or denies the saving power of His death ultimately rejects the gospel itself.
John answers every one of these claims by appealing to eyewitness testimony. His message is not philosophy or speculation. It is historical fact. If John were standing in a courtroom, his testimony would remain unchanged:
Jesus Christ is exactly who the apostles proclaimed Him to be—the eternal Son of God who truly became man.
The Stumbling Block of the Incarnation
Many people are comfortable speaking about Jesus as a spiritual influence or moral example. The difficulty comes when we proclaim that God became a particular man in a particular place, who gave particular commands, died on a particular cross, and now calls every person everywhere to submit to Him.
The incarnation is offensive because it removes our imagined autonomy.
If Jesus is God in human flesh, then His words carry absolute authority.
His commands are not suggestions.
His life becomes the standard for ours.
His death exposes our sin.
His resurrection demands our response.
As theologian John Piper observed, the greatest stumbling block is not simply believing that God became man. The greater offense is that every person must now bow before this one Jewish man. When God became man, humanity ceased being the measure of all things. Christ became the measure of all things.
That is why the incarnation remains offensive to the rebellious human heart. It confronts our desire to govern our own lives and calls us instead to joyful submission to Christ.
Fellowship Through Christ
John does not present these truths merely to win theological arguments. His goal is deeply pastoral.
He writes:
“…that you too may have fellowship with us; and indeed our fellowship is with the Father and with his Son Jesus Christ.” (1 John 1:3)
The gospel invites people into fellowship.
Through Christ we are reconciled to God and united with His people. Christianity is not simply agreeing with doctrinal statements. It is entering into the family of God through faith in His Son.
John then explains why he writes these things:
“…that our joy may be complete.”
True joy is found in fellowship with God.
As John Piper has famously said, “God is most glorified in us when we are most satisfied in Him.”
The more we treasure Christ, the greater our joy becomes.
Responding to the Truth
John’s opening verses call for more than intellectual agreement. They demand a response from our minds, hearts, and lives.
Believe the True Christ
Our faith must rest upon the Jesus revealed in Scripture.
He is not a Christ we reinvent according to our preferences. He is the eternal Son who became man, lived without sin, died for sinners, and rose again. Christianity stands or falls upon this historical reality.
If we misunderstand Jesus, everything else eventually crumbles.
Delight in Christ
John’s goal is not cold theology but complete joy.
Knowing the truth about Christ leads us into fellowship with the Father. We are no longer strangers or enemies of God. Through Jesus we have been welcomed into His family.
The gospel should fill our hearts with gratitude and delight. Jesus lived the life we could never live, died the death we deserved, and now freely gives eternal life to all who believe in Him.
Live Like Christ
Right belief produces right living.
Those who truly know Christ pursue holiness—not to earn salvation but because they have already received it. They obey His commands, fight against sin, love fellow believers, and seek to walk as Jesus walked.
John also reminds us that this fellowship is meant to be shared. We proclaim Christ so that others may enter into the same relationship with God that we ourselves have received.
The gospel never ends with us.
It sends us outward, inviting others into the family of God through faith in Jesus Christ.
The question remains as important today as it was when John first wrote this letter:
Who do you believe Jesus is?
Everything depends on that answer.
