As a synopsis or summary of the entire epistle, John combines belief in Jesus, love for one another, and obedience to God in this passage. The words "believe" or "faith" occur in vv. 1, 4, 5; "love" in vv. 1, 2, 3; "obey" or "commands" in vv. 2, 3. Together, all three activities find their fulfillment in God’s children, resulting in victory over the world. In addition, they provide a means of distinguishing authentic Christianity from mere appearances. John begins and ends his summary with the essence of Christianity: Belief in Jesus.

Verse 1
"Believes" is in the present tense, often indicating uninterrupted activity. Belief in Jesus is the present, continuous reality for all that have experienced new birth in Christ.

Whether belief has to do with affirming the complete humanity of "Jesus" (see also, 1 Jn. 2:18-23; 2 Jn. 1:7) or his complete deity "the Christ," John insists that affirming both are necessary for salvation and a sign of salvation.

Although John’s primary intent here is to show that persevering belief in Jesus is the consequence of being "born of God," it is also a condition for salvation (cf., Jn. 1:12; 20:31).

The Apostle includes another sign of true Christianity: Love. John draws from a general principle in families that sibling love is partially grounded in the reality of a common parentage. Therefore, if brothers and sisters naturally love one another, then so do God’s children naturally show love for one another (see 1 Jn. 4:7). Moreover, it is self-evident that to love the Parent is to love His children.

Verses 2-3a
John follows through with the Parent motif and speaks of another sign of genuine Christianity: Obedience. It is abundantly clear in John’s writings that there is a direct relationship between love and obedience (Jn. 14:15, 21, 23, 24; 15:10; 1 Jn. 2:5; 2 Jn. 1:6).

Biblically speaking, love for God is defined practically. It is never devoid of activity, although love does include affection (1 Jn. 3:17-18). It is important to note, however, that love and obedience are not the same thing. One is the result of the other. Love is to obedience as motivation is to activity. We do not love because we obey; we obey because we love. The manifestation of true love for God is obedience.

Note: John combines love for God and love for one another (vv. 1-3). Only those who have trusted the living God as revealed in the crucified and resurrected Jesus are enabled to obey the greatest commands to love God and one’s neighbor (see Rom. 5:5; 1 Jn. 4:7; Matt. 22:36-40). Keeping the first command is tantamount to keeping the second (1 Jn. 4:20-21).

Contrary to the "belief" in Jesus John already outlined, obedience is a consequence, not a condition, for being born of God.

To Consider: Living disobediently is an expression of contempt toward God. Conversely, living obediently is an expression of affection for God. Therefore, when I am living disobediently it is my love for God that has weakened and is in need of repair.

Verses 3b-4
God never demands more than He enables (1 Cor. 10:13). Also, Jesus promised that His burden would be light (Matt. 11:28-30). Although the way of obedience is no easy road, believers are promised God’s enablement and encouragement in the midst of life’s difficulties
(2 Cor. 1:3-4; 12:8-10).

Our duty to love one another is not beyond our capability to do so, because all of God’s children are provided the strength and desire to lovingly obey God and obediently love others.

Consequently, all Christians are victors over the world—that sphere of activity where Satan appears to rule (2 Cor. 4:4, 1 Jn. 5:19). Note: The neuter "whatever" (NASB, NRSV) is employed by John as a generic term to encompass all believers. John encourages us with two aspects to our victory:

We are presently, on a day-by-day basis, victorious over the world (note: "everyone born of God overcomes [present tense] the world."). The effects of victory are immediate and enduring.
Jesus’ victory, though in the past, is repeated in the life of every Christian, "This is the victory that has overcome (past) the world" (see Jn. 16:33). God "has rescued us from the dominion of darkness and brought us into the kingdom of the Son he loves" (Col. 1:13).
The means of our victory is "faith;" not faith of any kind, but faith in Jesus. Belief in Jesus is far more than a ticket to heaven. It is the basis of triumphant living here and now. The same faith that saves is the same faith that sanctifies. Faith in Jesus means there is no uncontrollable evil. Faith in Jesus means there is no irresistible temptation. Jesus’ mighty power has already conquered evil and temptation.

Verse 5
John asks a rhetorical question, which he already answered, to emphasize the central focus of Christianity: Belief in Jesus.

In 5:1 the content of true belief was that "Jesus is the Christ." Here John stresses belief that "Jesus is the Son of God." John may be treating the two titles synonymously (see esp., 2:22-23), because both indicate Jesus’ exalted status. Jesus refers to himself as both the "Son" (Mt. 11:27) and the "Christ" (Mk. 14:62).

John’s emphasis is that Jesus the Man is both the Christ (v. 1) and the Son of God. As such, a persistent confession of this truth ("who believes" is literally "the one who continually believes") results in the faithful supply of divine power to have victory over the world. The overcoming one is the believing one!

Summary
Belief, love, and obedience. These three combined are the hallmarks of authentic Christianity. For John the Apostle, being born of God through faith in God’s Son begins a life of obedience to God and love for our spiritual family resulting in victory over the world. Realizing that our foe has already been defeated is a tremendous encouragement to disciples both young and old. Praise God that we are more than conquerors through Christ!

 1 John 5:6-10