1John 3:15 Whosoever hates his brother is a murderer: and you know that no murderer has eternal life abiding in him.
The Greek word for hate is echthra meaning enmity (Luke 23:12; Rom. 8:7; Eph. 2:15-16; Jas. 4:4) and hatred (Gal. 5:20). It’s a bitter dislike, abhorrence, malice and ill will against anyone; tendency to hold grudges against or be angry at someone. Hatred seeks an occasion to provoke enmity and delights in brawls and fools hide resentment, plots, and even murder in their heart by lies and pretensions of holding no ill feelings over injuries received (Prov. 10:12, 18).
‘Murderer’ meaning manslayer [the Greek word anthropoktonos] and is used here and in John 8:44 for satan. What a terrible comparison, to be the same as the father of lies in hatred towards others. The Greek word for murder is phonoi which means to kill; to spoil or mar the happiness of another.
‘Eternal life’ and Jesus Christ is the same, we find in some scriptures that the term eternal life is synonymous with Jesus Christ (1:1-2; 2:24-25; 5:11-13, 20; John 14:6; 17:2-3). This life, like Christ, is eternal whether anyone ever receives it or not. Even if one receives it and then loses it, life is still eternal. Individual possession of it either temporarily or otherwise does not make it eternal or not eternal. So the argument that, if one should lose it, it would cease to be eternal, is wrong. Any eternal thing would not cease to be eternal just because the owner lost it. So it is with eternal life. Conditions must be met to get it and to keep it. Christ cannot and will not remain in the life where sin and rebellion dwell (John 15:4-8; Gal. 1:6-8; 2:6-7; Rom. 6:14-23; 8:1-13; 2Cor. 13:5).
We get eternal life now and keep it forever if we meet the following conditions: Come to Christ (John 6:37, 44, 45, 65); know God and Christ (John 17:2-3); cause no offense (Matt. 18:8-9); forsake all (Matt. 19:27-29; Mark 10:28-30); overcome sin (Rev. 2:7, 11, 17, 26; 3:5, 12, 21); live free from sin (Rom. 5:21; 6:16-23; 8:1-13; Tit. 2:11-14); fight the good fight of faith; lay hold on it (1Tim. 6:12, 19); be sober and hope to the end for it (Tit. 1:2; 3:7; 1Pet. 1:5, 9, 13); endure temptations (Jas. 1:12); love everybody (1Jn. 3:14-15); keep yourself in the love of God, looking for eternal life (Jude 1:20-24); be faithful unto death (Rev. 2:10; Heb. 12:14-15); believe and obey the gospel (John 3:15-19, 36; 4:14; 5:24; 6:40, 47, 54; 2Cor. 5:17; Rom. 1:5); be born again, hear Christ, and follow Him (John 3:1-36; 10:27-29).
Eternal life does not become an unforfeitable eternal possession until we enter into it (Matt. 7:13; 18:8-9; 19:17; Rom. 6:22); receive it (Rom. 6:23; Jas. 1:12; 1Pet. 1:13; Rev. 2:10); reap it (Gal. 6:7-8); and inherit it in the world to come (Matt. 19:27-29; Mark 10:28-30; Luke 18:28-30), and at the end of this life (Rom. 6:22).
‘Abiding in him’ eternal life and Christ are separate from the individual and always will be. They abide in one’s life like any other separate and outside something which one may permit to come into his life.