In reaching the climax of his epistle, John explicitly states the effects of belief in Jesus. As the ultimate Promise Keeper, God pledges to his people eternal life, answers to prayer, and a solid basis for assurance.

Assurance of Eternal Life (vv. 11-13)
The content of the testimony has already been stated, namely that Jesus as fully human and fully divine is the Son of God Who paid the price for sin and offers eternal life upon belief in Him.

The Person through whom eternal life is found is Jesus. There is no other (Acts 4:12; Jn. 14:6; 17:3), nor will there ever be another (Eph. 1:21). Throughout the Bible, there are three truths about eternal life:

• It is not a prize to be earned, but a gift to be received
• It is found in Jesus alone
• It is a present possession of all who believe in Jesus

Verse 13 is John’s purpose statement for writing this epistle. The Greek tense of "that you may know" (aorist subjunctive) indicates that assurance is not something gradually grown into, but is a present reality for all who believe. A degree of certainty is immediate upon faith in Jesus.

However, our certainty grows as we live obediently, love faithfully, and hold on to the promise of God. Therefore, it is not presumptuous to claim assurance where the conditions for receiving eternal life have been met. God never delays the benefits of His promises!

Assurance of Answered Prayer, (vv. 14-17)
Other conditions for answered prayer include obedience (3:22), abiding in Jesus’ words (Jn. 15:7), praying in Jesus’ name (Jn. 14:14), purity from sin (Is. 59:2; Ps. 66:18-19; Jn. 9:31). Here the condition is asking according to His will. We must want what God wants when we pray. Implicitly John is telling us that we don’t always know what God wants, so praying according to His will demonstrates our total dependency upon Him.

When these conditions are met, we can be assured of not only being heard but receiving answers. Therefore, believers should pray with expectancy (Mk. 11:24; Heb. 4:16).

John associates answered prayer with the seriousness of sin; a topic for which he has already demonstrated a great deal of concern (1:7-10; 2:21; 3:4-5, 8-9; 4:10). Two kinds of sin are mentioned:

1. Sin that does not lead to death
2. Sin that leads to death

It is best to limit the scope of "sin that leads to death" to that which John has already identified (denying Jesus as God Incarnate; habitual disobedience; loving the world and hating others). Sin that does not lead to death is episodic sin (Note: It is the "brother" that commits this sin), whereas sin that does lead to death is habitual.

To Consider: We must not be indifferent to each other’s sin. Although some would play judge, jury, and executioner, this extreme reaction doesn’t mean we should swing too far in the other direction and cease caring for one another’s spiritual maturity (Mt. 7:1-5; 18:15ff; Lk. 17:3). John summarizes by stating, in effect, "Though all wrongdoing is sinful, not all sin is mortal."

Our Basis for Assurance (vv. 18-21)
The grounds for Christian confidence is now made plain as John moves from certainty about answered prayer to certainty about three essentials:

1. The one who remains in sin cannot be born of God (v. 18). This is a recurring theme throughout First John (3:6, 9). Though sin is a present reality for all believers, so too is the power to overcome it.
2. As God’s children we have been rescued forever from the bonds of Satan (vv. 18b-19). Jesus is our Sustainer and Deliverer (Jn. 10:28; 17:12, 15). Not only do we have assurance of being God’s children; we also have assurance of being free from the prince of this world (Jn. 12:31; 14:30; 16:11).
3. Jesus alone reveals the true God (v. 20a). The object of all religious truth is not abstract, but profoundly personal. Genuine believers are given insight by Jesus Who has the exclusive right to reveal the Father (Mt. 11:27; Lk. 2:28-33; Jn. 1:18; 14:9). As God’s children our entire identity begins and ends "in him who is true" (see also 2:5; 2:24; 4:13-16).

John issues a final warning against idolatry (v. 21). Having just proclaimed that Jesus alone reveals God, it makes sense for John to warn against any false manifestation or representation of God. A false view of the Son is identical to a false view of God. Though God "keeps" us ultimately (2 Thess. 3:3; Jude 1), this does not preclude personal effort to actively guard ourselves from false beliefs (2 Pt. 3:17).

Since John’s primary christological concern is the identity of Jesus, verse 21 could be a reference to an idolized Jesus that is false. Still, an idol, in the broadest sense, is anything which occupies the place of God. Therefore, John warns us to avoid the errors identified in his epistle and stay on track (i.e., abide, remain, continue) with the truth he proclaims.

Summary
Assurance of eternal life is based upon three tests: Obeying God (the moral test); believing the truth about Jesus (the doctrinal test); and loving our spiritual family (the social test). Throughout his epistle John encourages us that we are born of God, we know God, we are in God, and we possess eternal life from God. Our willing response is simply to offer every waking moment to God in praise and thankfulness for all he has done. In doing so, we rest in God’s promise of everlasting life through Jesus Christ his Son.

Soli Deo gloria!