1 John 5:13
I write these things to you who believe in the Name of the Son of God, that you may know that you have eternal life. (ESV)
The Main Idea: Because the eternal life of the Son of God has been historically revealed, gloriously accomplished, and really given to sinners through faith in the crucified and risen Christ, the person who is truly born of God will show it by believing rightly about Jesus, walking obediently before God, and loving the brothers and sisters sincerely, and it is upon this Christ, confirmed by this fruit, that assurance of salvation rests, not upon the shifting sands of our feelings.
1. The Purpose of the Letter: Written That You May Know
1.1 John writes as an eyewitness, not as a mystic
1.2 The stated aim: Fellowship and full joy
1.3 The explicit purpose statement: (1 John 5:13).
2. Three Recurring Tests of Genuine Faith
2.1 The Doctrinal Test: What do you believe about Christ?
2.2 The Moral Test: Do you walk in obedience?
2.3 The Relational Test: Do you love the brothers and sisters?
3. Three Theological Pillars Undergirding the Tests
3.1 God is Light (1 John 1:5)
3.2 God is Love (1 John 4:8, 16)
3.3 God is Life (implicit throughout; explicit in 1 John 5:11–12)