1. II. Light and Darkness (1:5-2:24)
    1. A. Warning Against False / Prideful Self-Assessments (1:5-1:10)
Thematic Relation: Action must follow deed, or we are not one with God

Some Key Words

Walk (peripateo [4043]):
To progress, make due use of opportunity; be occupied with.
Truth (aletheia [225]):
unveiled reality behind the appearance.
Sin (hamartia [266]):
missing the true purpose of our lives (God). Offense to God with emphasis on guilt.
Righteous (dikaios [1342]):
acting conformably to justice and right without any failure. One whose way of thinking, feeling, and acting is wholly conformed to the will of God.
Forgive (aphiemi [863]):
to send away; dismiss. to remit; forgive debts. To liberate from the power of sin.
 

Paraphrase

5 God is pure, 6 and those who say they are His must be pure as well. 7-10 Tests are offered to judge our own purity.

Key Verse

1:8 - This sums up the situation nicely. To deny our sinfulness is to deceive ourselves, and to show by proof that truth (which is in Christ and is Christ) is not in us.

Thematic Relevance:

 Love will show in obedient conformance to the one loved. The fellowship noted above requires such a conforming love. You cannot be united in purpose yet at odds in action.

Doctrinal Relevance:

 7 Our fellowship with God is made possible by the work of Jesus His Son. 9 Forgiveness requires action on our part: confession to God.

Moral Relevance:

 We are told in Scripture to judge ourselves. Here are some tests to accomplish that. The sum of them all is that we must act according to our professed belief, or our professing is meaningless.

Some Parallel Verses

1:5
1Ti 6:16 - God lives in unapproachable light, unseeable by imperfect man. Jas 1:17 - God does not change.
1:6
Jn 8:12 - Christ the light of life, dispelling the darkness of sin in us. Jn 8:55 - to know God is to keep His word. Jn 3:21 - the truthful love the light, and come to it to reveal God's work in them.
1:7
Isa 2:5 - we are invited to walk in God's light. Ti 2:14 - Christ redeemed and purified us by His giving of Himself.
1:8
Job 15:14 - No man is pure or righteous. Pr 20:9 - Nor can he claim to have cleansed and purified himself from sin. Ro 3:10 - none is righteous. Jas 3:2 - for all stumble in many ways.
1:9
Ps 32:5 - We are to admit our sins to God, and thus He will forgive us. Pr 28:13 - for the one who seeks to hide his sins is ruined, but the confessor finds compassion. Ti 2:14 - through Christ's redeeming work.
1:10
Jn 3:33 - God is true.

New Thoughts

There are two sets of parallels here. The first group shows the ways in which this test is failed:
1:6 - if we say we have fellowship with God but walk in darkness then we lie and don't practice truth
1:8 - if we say we have no sin then we deceive ourselves and truth isn't in us.
1:10 - if we say we have not sinned then we claim God lied and His Word isn't in us.
From the parallels, we can conclude that to deny our sinful state is sinful in itself. For it denies not only the truth of our own condition, but denies the truthfulness of God's Word. Not a good place to be in.

In contrast, we have to parallels of the test passer:
1:7 - if we walk as He walks, then we have fellowship and are cleansed from all sin by Christ Jesus.
1:9 - if we confess our sins, then He forgives us our sins and we are cleansed from all unrighteousness.
The first of these directly addresses the first failure. The walk and the fellowship must match. To walk otherwise would be to have fellowship with the devil. The second brings us to the place claimed by the failures, only by admitting our natural state, can we attain to the stature of "one whose way of thinking, feeling, and acting is wholly conformed to the will of God". This is only going to come to us by God's grace through Christ's work.