1 John 4:17 Love has been perfected among us in this: that we may have boldness in the day of judgment; because as He is, so are we in this world. 18 There is no fear in love; but perfect love casts out fear, because fear involves torment. But he who fears has not been made perfect in love. 19 We love Him[b] because He first loved us.
Obedience by Faith

   
20 If someone says, “I love God,” and hates his brother, he is a liar; for he who does not love his brother whom he has seen, how can[c] he love God whom he has not seen? 21 And this commandment we have from Him: that he who loves God must love his brother also.

1 John 5

 1 Whoever believes that Jesus is the Christ is born of God, and everyone who loves Him who begot also loves him who is begotten of Him. 2 By this we know that we love the children of God, when we love God and keep His commandments. 3 For this is the love of God, that we keep His commandments. And His commandments are not burdensome. 4 For whatever is born of God overcomes the world. And this is the victory that has overcome the world—our[a] faith. 5 Who is he who overcomes the world, but he who believes that Jesus is the Son of God?

4:17  With us (met' hmwn).
Construed with the verb teteleiwtai (is perfected). In contrast to en hmin (verses 12,16), emphasising cooperation. "God works with man" (Westcott). For boldness (parrhsian) in the day of judgment (only here with both articles, but often with no articles as in 2 Peter 2:9) see 1 John 2:28.

 

As he is (katwv ekeinov estin).
That is Christ as in 2:6; 3:3,5,7,16. Same tense (present) as in 3:7. "Love is a heavenly visitant" (David Smith). We are in this world to manifest Christ.

4:18

Fear (pobov).
Like a bond-slave (Romans 8:15), not the reverence of a son (eulabeia, Hebrews 5:7) or the obedience to a father (en pobwi, 1 Peter 1:17). This kind of dread is the opposite of parrhsia (boldness).

 

Perfect love (h teleia agaph).
There is such a thing, perfect because it has been perfected (verses 12,17). Cf. James 1:4.

 

Casteth out fear (exw ballei ton pobon).
"Drives fear out" so that it does not exist in real love. See ekballw exw in John 6:37; 9:34; 12:31; 15:6 to turn out-of-doors, a powerful metaphor. Perfect love harbours no suspicion and no dread (1Co 13).

 

Hath punishment (kolasin exei).
Old word, in N.T. only here and Matthew 25:46. Timwria has only the idea of penalty, kolasiv has also that of discipline, while paideia has that of chastisement (Hebrews 12:7). The one who still dreads (poboumenov) has not been made perfect in love (ou teteleiwtai). Bengel graphically describes different types of men: "sine timore et amore; cum timore sine amore; cum timore et amore; sine timore cum amore."

v. 19

He first (autov prwtov).
Note prwtov (nominative), not prwton, as in John 20:4,8. God loved us {before} we loved him (John 3:16). Our love is in response to his love for us. Agapwmen is indicative (we love), not subjunctive (let us love) of the same form. There is no object expressed here.
v. 20
If a man say (ean tiv eiphi).
Condition of third class with ean and second aorist active subjunctive. Suppose one say. Cf. 1:6.

 

I love God (Agapw ton teon).
Quoting an imaginary disputant as in 2:4.

 

And hateth (kai misei).
Continuation of the same condition with ean and the present active subjunctive, "and keep on hating." See 2:9; 3:15 for use of misew (hate) with adelpov (brother). A liar (pseusthv). Blunt and to the point as in 1:10; 2:4.

 

That loveth not (o mh agapwn).
"The one who does not keep on loving" (present active negative articular participle).

 

Hath seen (ewraken).
Perfect active indicative of oraw, the form in John 1:18 used of seeing God.

 

Cannot love (ou dunatai agapain).
"Is not able to go on loving," with which compare 2:9, ou dunatai amartanein (is not able to go on sinning). The best MSS. do not have pwv (how) here.
5:1
That Jesus is the Christ (oti Ihsouv estin o Xristov).
The Cerinthian antichrist denies the identity of Jesus and Christ (2:22). Hence John insists on this form of faith (pisteuwn here in the full sense, stronger than in 3:23; 4:16, seen also in pistiv in verse 1 John 5:4, where English and Latin fall down in having to use another word for the verb) as he does in verse 5 and in accord with the purpose of John's Gospel ( 20:31). Nothing less will satisfy John, not merely intellectual conviction, but full surrender to Jesus Christ as Lord and Saviour. "The Divine Begetting is the antecedent, not the consequent of the believing" (Law). For "is begotten of God" (ek tou teou gegennhtai) see 2:29; 3:9; 4:7; 5:4,18. John appeals here to family relationship and family love.

 

Him that begat (ton gennhsanta).
First aorist active articular participle of gennaw, to beget, the Father (our heavenly Father).

 

Him also that is begotten of him (ton gegennhmenon ex autou).
Perfect passive articular participle of gennaw, the brother or sister by the same father. So then we prove our love for the common Father by our conduct towards our brothers and sisters in Christ.

v .2

Hereby (en toutwi).
John's usual phrase for the test of the sincerity of our love. "The love of God and the love of the brethren do in fact include each the other" (Westcott). Each is a test of the other. So put 3:14 with 5:2.

 

When (otan).
"Whenever" indefinite temporal clause with otan and the present active subjunctive (the same form agapwmen as the indicative with oti (that) just before, "whenever we keep on loving God."

 

And do (kai poiwmen)
"and whenever we keep on doing (present active subjunctive of poiew) his commandments." See 1:6 for "doing the truth."

v.3

--that (ina).
Explanatory use of ina with auth, as in John 17:3, to show what "the love of God" (1 John 4:9,12) in the objective sense is, not mere declamatory boasting (4:20), but obedience to God's commands, "that we keep on keeping (present active subjunctive as in 2:3) his commandments." This is the supreme test.

 

Are not grievous (bareiai ouk eisin).
"Not heavy," the adjective in Matthew 23:4 with portia (burdens), with lupoi (wolves) in Acts 20:29, of Paul's letters in 2 Corinthians 10:10, of the charges against Paul in Acts 25:7. Love for God lightens his commands.

v.4

For (oti).
The reason why God's commandments are not heavy is the power that comes with the new birth from God.

 

Whatsoever is begotten of God (pan to gegennhmenon ek tou teou).
Neuter singular perfect passive participle of gennaw rather than the masculine singular (verse 1) to express sharply the universality of the principle (Rothe) as in John 3:6,8; 6:37,39.

 

Overcometh the world (nikai ton kosmon).
Present active indicative of nikaw, a continuous victory because a continuous struggle, "keeps on conquering the world" ("the sum of all the forces antagonistic to the spiritual life," D. Smith).

 

This is the victory (auth estin h nikh).
For this form of expression see 1:5; John 1:19. Nikh (victory, cf. nikaw), old word, here alone in N.T., but the later form nikov in Matthew 12:20; 1 Corinthians 15:54,57.

 

That overcometh (h nikhsasa).
First aorist active articular participle of nikaw. The English cannot reproduce the play on the word here. The aorist tense singles out an individual experience when one believed or when one met temptation with victory. Jesus won the victory over the world (John 16:33) and God in us (1 John 4:4) gives us the victory.

 

Even our faith (h pistiv hmwn).
The only instance of pistiv in the Johannine Epistles (not in John's Gospel, though in the Apocalypse). It is our faith in Jesus Christ as shown by our confession (verse 1) and by our life (verse 2).