First John is the first and longest of three letters in the New Testament that were written by the Apostle John. John was a unique disciple. Along with his brother James and Simon Peter, he was part of the inner circle of Jesus’s disciples. Before being called by Jesus he was a disciple of John the Baptist. Just imagine the things John had seen and heard and handled (v.1) as he sat at the feet of the forerunner of Jesus (John the Baptist) and the Messiah Himself!
In classical art John is often portrayed as a meek, quiet young man with an effeminate bearing, but that image is hardly accurate. Jesus gave John and his brother the nickname “Sons of Thunder” because of their volatility and their assertiveness (see Mark 3:17, Mark 9:38, Mark 10:35-41, Luke 9:51-55). John was a man of the sea, a fisherman before being called as a disciple. He called himself “the disciple whom Jesus loved” (see John 21:20). The love of Jesus transformed the man with the stormy personality into a loving (but still gritty!) pastor. John is also known as “John the Revelator” because he wrote the book of Revelation and “John the Evangelist” because he wrote the Gospel of John. He was the only one of the apostles who was not martyred, although he was harshly persecuted. John wrote from a position of authority, but with a great deal of love. He wrote this letter as a pastor to the churches of Asia Minor which were under his oversight until his death.
Unlike the other apostles, John lived long enough to shepherd a new generation of believers at the close of the First Century. It was a precarious time in the church, with the constant threat of persecution and the blight of false teachers. In this first chapter, John confronted false teaching with the truth. (Note: John used the opposite images of light and darkness to represent the difference between truth and error, good and evil, holiness and sin. He learned that from Jesus; see John 3:19-21.)
John had walked and talked with Jesus. He was the only disciple present at the cross. He personally saw Jesus die, he personally looked into the empty tomb, he personally met with Jesus after His resurrection, and he personally witnessed His ascension into heaven. When it came to the truth about Jesus, John knew what he was talking about (v.1-3)! He wrote in order to set the record straight about what it means to know Jesus and to experience the joy of salvation (v.4).
Wasting no time in confronting false teaching head-on, John wrote in verses 5-10 to correct a set of erroneous doctrines that had gained traction in the church. The lie that was being taught was basically a denial of sin. False teachers, borrowing from mysticism and Greek philosophy, confused people by mingling the gospel with the idea that sin doesn’t matter, it doesn’t exist. They reasoned that since God is spiritual in nature, our physical bodies — and any “sin” we commit while in them — don’t really matter. So they denied their sinfulness (v.8), and in doing so they denied their need for forgiveness and they denied the necessity of Jesus shedding His blood on the cross.
Furthermore, they taught that believers could “walk in the light” of fellowship with God in a spiritual sense (in their minds and hearts) while indulging in the “darkness” of all kinds of lusts and pleasures in the physical sense (v.6). John refuted the idea: “If we say we have fellowship with God while we walk in darkness we lie.” We cannot truly know God and fellowship with Him until the barrier of sin is removed (v.7). It was the sacrifice of Jesus on the cross that opened the door to fellowship with God, and unless we confess our need for forgiveness and walk through that door as repentant sinners, we will remain in the dark (v.7-8). The good news of the gospel is that when we confess our sin and our need for grace, God forgives us and cleanses us completely (v.9)! This promise is not only operative at the moment we are born again. It continues as we live in a state of repentance and confession for the remainder of our lives on earth — every time we confess a sinful act, word, thought, or attitude, God is faithful to forgive. Claim that promise today, and you will walk in the light (v.7).