←1 John 1→BSB

We proclaim to you the one who existed from the beginning: That is, from before time began, eternally (John 8:58). When Jesus came in the flesh (John 1:14), the apostles saw him . . . and touched him. This affirmation that they actually touched the Word of life is important because Gnosticism and Docetism (early Christian heresies) denied that Christ was truly a human being (see 1 Jn 4:2–3). Jesus, the Son of God, is the personal expression of the invisible God, and the giver of eternal life (John 1:1–4).

• life itself (Greek zōē): Throughout the New Testament, this word is used to designate the eternal life of God (e.g., Eph 4:18). This life resides in Christ, and he makes it available to all who believe in him.
• This one . . . was revealed to us: Jesus, the Christ, was known to his apostles as a human being during his earthly ministry.

• what we . . . have actually seen: The Word of life had, as a man, revealed God to the apostles.
• our fellowship is with the Father and with his Son: Once the Spirit regenerated the apostles, they entered into spiritual fellowship with the Father and the Son.
• you may have fellowship with us: Whoever entered into fellowship with the apostles by associating with them while they were alive, or enters now by remaining in their teaching, has fellowship with the Father and the Son through them.

so that you may fully share our joy: The joy that the apostles have comes from their fellowship with God the Father and the Son (1:3). Readers will share this joy when they enter into the same fellowship.

God is light: This light shone through Jesus Christ to all he came in contact with, to expose their sin and to illumine the moral nature and character of God (see John 1:4–5, 9; 3:19–21; 8:12; 9:5; 12:35–36, 46). In the writings of John, “light” represents God’s holiness and revelation. It is the opposite of false teaching and undisciplined living, which is “darkness” (1 Jn 1:6).

This is the first of several instances in which John challenges the claims of the Gnostics, who had broken away from the apostolic fellowship and were thus living in spiritual darkness. They claimed to have fellowship with God but did not express his character, which is light. Jesus had warned the Jewish leaders of his day not to let the light they thought they had be darkness (Matt 6:23)—their religious beliefs had blinded them to the spiritual illumination they could have received from Christ. In like manner, these Gnostic teachers thought they were enlightened but were actually darkened by their so-called illuminations. They claimed to have spiritual experiences from God, yet they rejected fellowship with the ones who had actually seen God in the flesh, namely, John and the other apostles.

Believers have fellowship with each other and with God as they live in the light. People cannot say they commune with God and then refuse to have fellowship with God’s people. This was the case with the Gnostics. The apostles of Christ had known Jesus Christ as God-in-the-flesh and were continuing to have spiritual fellowship with him (1:3).

If we claim we have no sin: This is the second false claim of the Gnostics (see 1:6). They claimed that they were or could be sinless since Christ had abolished their sins once and for all—their higher knowledge would lift them above the realm of sin. But Christians do still sin when they live in their old nature (see Rom 7:14–25). The true Christian both acknowledges this sin (1 Jn 1:9) and trusts in Christ to take it away.

To maintain continual fellowship with God, we need to confess our sins to him. Forgiveness and cleansing are guaranteed because God is faithful to his promises and because he acts on the basis of his justice. Christ’s death for our sins fulfills God’s justice and acquits us of our guilt.

If we claim we have not sinned, we are calling God a liar: God’s word emphasizes the permeating and penetrating nature of sin (see study note on 1:8).