3:1 How great [Gr. word “potapen” refers to something that has come from another country; something exotic or beyond what we have previously experienced] is the love the Father has lavished [poured] on us, that we should be called children [word emphasizes birth rather than infancy] of God [“children of God” is both a reality and a title for believers]! And that is what we are [in the present, not at some future point]! The reason the world does not know us is that it did not know him [cf. Jn. 1:10].
3:2 Dear friends [beloved or those who are loved], now [not at some time in the future] we are children of God, and what we will be has not yet been made known. But we know that when he appears, we shall be like him [we will be like Him in body (cf. Phil. 3:21); glorification (the final stage of salvation)], for we shall see [to perceive, to recognize, to appreciate] him as he is [we will see Jesus as Savior and Lord; those who reject Him will see Him as Judge; cf. 2 Cor. 3:18].
3:3 Everyone who has this hope in him purifies [morally and spiritually; cf. Matt. 5:8] himself, just as he is pure.
3:4 Everyone who sins breaks the law; in fact, sin is lawlessness.
3:5 But you know that he appeared so that he might take away our sins. And in him is no sin.
3:6 No one who lives in him keeps on sinning. No one who continues to sin has either seen him or known him.
3:7 Dear children, do not let anyone lead you astray. He who does what is right is righteous, just as he is righteous.
3:8 He who does what is sinful is of the devil, because the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the devil’s work.
3:9 No one who is born of God will continue to sin, because God’s seed remains in him; he cannot go on sinning, because he has been born of God.
3:10 This is how we know who the children of God are and who the children of the devil are: Anyone who does not do what is right is not a child of God; nor is anyone who does not love his brother.
3:11 This is the message you heard from the beginning [from the time John’s readers first became believers (cf. 1 Jn. 2:7); cf. Jn. 13:34-35; 15:17]: We should [not an option; an obligation] love one another.
Note: What keeps you from loving others?
3:12 Do not be like Cain [along with Abel, son of Adam and Eve; read Gen. 4:1-16; Heb. 11:4; Cain offered grain and fruits for his offering], who belonged to the evil one [cf. Jn. 8:44] and murdered his brother [Abel; offered an animal sacrifice (with the right attitude)]. And why did he murder [one of the results of failing to love others] him? Because his own actions were evil and his brother’s were righteous [Cain angered by Abel’s righteous life].
Note: How can jealousy and hatred lead to murder?
3:13 Do not be surprised, my brothers, if the world [hostile to God (cf. 1 Jn. 2:15)] hates [because believers are different (cf. 1 Pet. 4:3-4)] you [cf. Jn. 5:18-19].
3:14 We know [John used the Greek verb translated “we know” sixteen times in this letter] that we have passed [something experienced in the past with continuing results] from death to life, because we love [love is outward evidence that a person has passed from death to life] our brothers [other Christians]. Anyone who does not love remains in death.
3:15 Anyone who hates his brother [another Christian] is a murderer [cf. Matt. 5:21-22 re: violating the spirit of the Sixth Commandment through anger and verbal abuse], and you know that no murderer has eternal life in him.
Note: If a heart is empty of love, what fills in the void?
3:16 This is how we know what love is: Jesus Christ laid down [voluntarily] his life for us [stresses the reality of Christ’s death]. And we ought to lay down [we can do this by giving up personal rights, seeking the best for others, putting the interests of others above our own, serving others without expecting anything in return; cf. Jn. 15:13] our lives for our brothers.
Note: How can we “lay down” our lives for others?
3:17 If anyone has material possessions [the necessities of life; cf. Lk. 12:48] and sees his brother in need [real need, not wants] but has no pity [locks or shuts up compassion; “shuts up his heart” (NKJV)] on him [cf. parable of the good Samaritan (Lk. 10:25-37)], how can the love [Biblical love is a verb; love must take action] of God [God’s kind of love which expressed itself in giving (cf. Jn. 3:16; Rom. 5:8)] be in him [cf. Jas. 2:14-17]?
3:18 Dear children, let us not love with words or tongue [talk is cheap] but with actions [actions must back up words] and in truth.
Note: “They love one another. They never fail to help widows; they save orphans from those who will hurt them. If they have something, they give freely to the man who has nothing; if they see a stranger, they take him home and are happy, as though he were a real brother. They don’t consider themselves brothers and sisters in the usual sense, but brothers instead through the Spirit, in God.” (Written by Aristedes about Christians to the Roman Emperor Hadrian)
3:19 This [actively demonstrating God’s love to others in practical ways] then is how we know that we belong to the truth, and how we set our hearts at rest in his presence
3:20 whenever our hearts [or consciences] condemn us. For God [His voice of assurance] is greater than our hearts [the accusing voice of conscience], and he knows everything [God knows more about us than we know about ourselves].
3:21 Dear friends, if our hearts do not condemn us, we have confidence [the assurance that we are accepted; freedom of speech in approaching God in prayer; cf. Heb. 4:16] before God
3:22 and receive from him anything we ask [cf. Jn. 15:7 (prayers must pertain to fruitbearing and glorifying God); cf. Matt. 7:7; 21:22], because we obey his commands and do what pleases him [cf. Jn. 9:31].
3:23 And this is his command:  to believe [implies a decisive action] in the name of his Son, Jesus Christ, and  to love [ongoing lifestyle] one another [believing in Jesus requires that we love others who believe in Him] as he commanded us.
3:24 Those who obey his commands [cf. 1 Jn. 3:23] live in him, and he in them. And this is how we know that he lives in us: We know it by the Spirit [provides believes with the presence of the indwelling Christ] he gave us.
Note: Does your conduct verify the presence of the Holy Spirit in your life?