The apostle wrote this letter to his dear “little children” (the phrase is used nine times) to help them find assurance of personal salvation (5:13). When you are sure of your salvation, you can have fellowship with God and God’s people (1:3), experience joy (1:4), and have victory over sin (2:1–2). John also wrote to warn believers about false teachers (2:26–27; 4:1–6). Both Peter and John were concerned about purity of doctrine in the church; and we should be, too.
Chapters 1–2 focus on fellowship and contrast saying and doing. It is easy to talk the Christian life, but God wants the walk. John emphasizes sonship in chapters 3–5 (the phrase “born of God” is used several times) and gives three marks of the true child of God: doing God’s will (chap. 3), loving the brethren (chap. 4) and believing the truth (chap. 5).
“God is light” (1:5), and His children should walk in the light. “God is love” (4:8, 16), and His children should walk in love. “The Spirit is truth” (5:6), and God’s children should believe and obey the truth.
