I John 1–2:2. Introduction to Life and Light.

Key Notes: Three views of Jesus' human body. Objectives of Gospel of John and I John. God is.... If we sin....

John is the beloved disciple who wrote the Gospel of John, these three general letters, and the Revelation. The general epistle of John was written to refute the work of false teachers, as were Peter's two letters.

Greek philosophy influenced Christian truth in the earliest days of the Church. Perhaps in reaction to Greek/Roman religion in which the gods were very human in their behaviors, often despicable, some Christians invented a heresy (Docetism) which denied that Jesus was human. It was impossible, they thought, that God could be born in a human way, and suffer and die. Therefore Jesus was a divine spirit-being that appeared human, but He would not leave a footprint.

A related heresy was taught by Cerinthus, a contemporary of John, that the Christ-deity came upon the human Jesus at his baptism, and left at His crucifixion.
"Jesus was not born of the virgin but rather he was the son of Joseph and Mary, just like all other men, but more powerful in righteousness, intelligence and wisdom. After the baptism, Christ descended upon him with the authority which is above all....But at the end Christ again departed from Jesus and (only) Jesus suffered and rose again. Christ however remained impassible, since he was a spiritual being."--quoted by Irenaeus.

A third option was offered later by Basilide:, Simon of Cyrene was crucified in Jesus' place. Moslems adopted this fabrication, as seen in the Koran.
   "They said 'We killed Christ Jesus, the son of Mary, the Apostle of God'--but they killed him not, nor crucified him, but it was made to appear so to them. And those who differ therein are full of doubts." Koran 4:157.

All three efforts deal with the seemingly impossible, that Jesus was at the same time true God and true Man, and that He could die. Notably, these heretical groups of Cerinthus and Basilides, were morally loose and unloving. Since the body was inevitably sinful, and only the spirit was righteous, whatever the body did was of no moral consequence. John will also deal with these heresies as well as dealing with loose attitudes toward sin.
See John Stott's introduction to "The Epistles of John." Tyndale,’64. p46–47.

If we compare the Gospel of John and I John, four parallel ideas are presented to their audiences.Their objectives are different.

Gospel of JohnI John
to those doubting His Deityto those doubting His humanity
to bring unsaved to faith 20:31to give believers assurance 5:13
to receive life 10:10to know that they have life 3:14
seven signs to evoke faithfive tests to evaluate faith

1:1–4 John opens the book in a whisper of ecstatic speech. We heard, we saw, we looked upon and handled It---the Word of Life. (The Greek words "Word" and "Life" require the impersonal pronoun "it.") Then he says " it" again in a five-part time sequence:
• the eternal Life (Jesus) was with the Father,
• It was manifest to us;
• we saw, heard and proclaim It to you,
• that our fellowship may be with each other and with the Father and Son,
• that our joy may be complete.

Comment:
John is now quite old, but he still is overwhelmed by the thought that he knew Jesus, the Son of God, here referred to as the Word of Life. The heretics denied Jesus' true nature, His incarnation, but they were speculating at a distance. John was there, as close to Jesus as anyone. (Jn.13:23). He knew Jesus was real, and he knew that He was really God: he put the Father and the Son on an equal footing in our fellowship with them.

We note that the goal of Jesus' work is here not called salvation or redemption, but fellowship with God. That is a consummation of salvation--atonement-- and it is beyond our understanding.

"God is light...." There are three other "God is...." statements in the NT. They are unique and arresting.
God is love. IJn.4:8,16
God is Spirit. Jn.4:24
God is a consuming fire. Heb.12:29

God is Light. Light is not an abstraction, but a projection of His Glory. (Heb.1:3; IICor.4:6). Light also shows us the way (Psa.119:105), and reveals sin which hides in the darkness. Jn.3:19

John at once makes a moral application. Observe the three-fold parallel construction.
1:6–2:2.
 If we say that we have fellowship with Him but walk in  darkness,
          we lie and do not live according to the truth.
               If we walk in the light as He is in the Light we have fellowship with one another and the blood of Jesus, His Son, cleanses us from all sin.

If we say
that we have not sin,
          we deceive ourselves and the truth is not in us.
               If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.
 If we say we have not sinned,
          we make Him a liar and His word is not in us.
               If anyone does sin, we have an advocate with the Father, Jesus Christ the Righteous.

Sin is a most unpopular subject. For one wing of the Christian Church, sin is a problem already dealt with, and we are on our way to perfection. For another group, sin is due to lack of self-esteem. For yet another, sin is the daily threat of losing one's salvation. But even if we walk in the Light as He is in the Light and have fellowship with one another, the Blood of Jesus still must continually be available to cleanse us from all sin.

Have we no sin--now? It is amazing to see a young person profess great spirituality while living in debauchery. {"What I do is not sin."} That is a gross deception. If we confess, He will forgive.

Do we think we have never sinned? {"I don’t lie or steal or kill people."} God makes it clear that all have sinned (Rom.3:23; Psa.14:1–3; Isa.59:7,8).To say otherwise is to contradict God.

Behold God's mercy and patience with our self-justification. Seek the cleansing that is available to you, every day.
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John Stott's commentary on I John is the best I have found. _____________________________________