Confession must be personal. He told us that this God is distinct from the person of God the Father. If we say we have no sin: John has introduced the ideas of walking in the light and being cleansed from sin. God has put a desire for relationship in every one of us, a desire He intended to be met with relationships with other people, but most of all, to be met by a relationship with Him.
We really can have a living, breathing relationship with God the Father, and with Jesus Christ. Actually, for many people this is totally unappealing.
This was real, and John tells us about it as an eyewitness. And walk in darkness: John speaks of a walk in darkness, indicating a pattern of living. This does not speak of an occasional lapse, but of a lifestyle of darkness. Beloved, do not misunderstand me — no man can have fellowship with God unless sin be taken away; but his fellowship with God, and his walking in light, does not take away his sin — not at all.
Such is the grace of our God, and of His Son. The one who confessed his sin was the one who agreed with God about how bad he was.
Whoever, or whatever, John wrote of, he said his subject was eternal and therefore was God because the subject existed before all else and was the source and basis of the existence of all things. To think this of ourselves is to deceive ourselves, and to say this of ourselves is to lie — the truth is not in us.
Yet we can still walk in the light, so John does mean perfect obedience.