You will find an introduction and outline of 1 John, here.
A prayer from Gregory of Nazianus [ (329-389) an early Church father] for your use before reading.
I.1:1-4 The Prologue: The Word of Life: Compare this prologue with the Gospel of John’s prologue. How are they similar? How are they different? The prologue introduces many of the letter’s themes: The Incarnation, the kind of life revealed by Christ and the importance of community in that life.
II. 1:5-2:27 Light Among God’s Children: God is light…
A. 1:5-2:2 The Incompatibility of Light and Sin: These verses are commonly used in confession liturgies. There are six “if, then” statements in this section. Three of them quote the opponent’s errors and then declare the consequences. The other three are assurances.
B. 2:3-11 Love as a Test of Knowledge: Now three “whoever says…” statements. Knowledge of God is evidenced in the way a believer lives. See John 13:34, 15:12.
C. 2:12-17 Conflict in the World: “little children” may mean the entire Christian group. “Fathers” may mean aged and “Young people” youth. Or these verses may mean children, fathers, young people. The “world” in this use does not mean the created world but refers to the things that are under the power of evil.
D. 2:18-27 Conflict within the Community: The author does not tell us what the conflict was, only that some have left the community. Those who have left are called “antichrists”. Is this use of the word “antichrist” new or different? Or is this a way you understand the word should be used?
III. 2:28-4:6 Righteousness Among God’s Children: a common assumption in the ancient world was that children would be like their parent. Therefore children of God are…
A. 2:28-3:10 The Hope of the Righteous: another familiar verse, 3:1. The Johnannine world view was often characterized by opposites, light/dark, truth/falsehood, sin/righteousness. Sin in this usage is not immorality or rule breaking but is unbelief.
B. 3:11-24 The Love of the Righteous: “The clearest sign of sin is the lack of love.” (Culpepper, 1180) 3:19-21 might be interpreted in more than one way, but taken with the rest of the section seems to focus on assurance.
C. 4:1-6 The Two Spirits: the Spirit of truth v. the spirit of deception. These verses contain a clue about the division in the community. Apparently those who have left denied or diminished the importance of Jesus humanity.
IV. 4:7-5:12 Love Among God’s Children
A. 4:7-21 The True Nature of Love: A beautiful discussion of God’s love and human love. What are the relationships between God and God’s people and between God’s people to be? Where does love come from? How is God’s love shown?
B. 5:1-12 The True Nature of Faith
V. 5:13-21 Epilogue
Read More About It
Culpepper, R. Alan “1,2,3 John” in HarperCollins Bible Commentary, rev. ed.James L Mays, ed. (New York: Society of Bible Literature) 2000.
Johnson, Luke Timothy, The Writings of the New Testament: An Interpretation, rev. ed. (Minneapolis:Fortress Press) 1999. Chapter 25, “1,2, and 3 John
Miller, Donald G.; Pheme Perkins “1 John” in The New Oxford Annotated Bible, Bruce M. Metzger, Roland E. Murphy eds. (New York: Oxford University Press) 1994.