The person who claims he is continuing to live in [fellowship with] Jesus should also live the way He did.

I did not write to you people because you are ignorant of the truth [about these matters], but because you do know it, and because nothing false belongs to the true teaching.

not [hate each other] the way Cain did, who belonged to the evil one [i.e., Satan], when he murdered his brother [Abel]. And why did he murder him? It was because his [own] actions were evil and his brother's were righteous [See Heb. 11:4].

[For] we [can] know that we have passed out of [the realm of spiritual] death and into [spiritual] life, because we [show] love for the brothers [and sisters]. The person who does not love [them] continues to be [spiritually] dead.

Every person who believes that Jesus is the Christ [i.e., God's specially chosen one] has been [spiritually] conceived [and eventually born] by God. And everyone who [continually] loves God, who did the conceiving, also [must continually] love the person whom God has [spiritually] conceived.

This Jesus is the one whose coming [to earth was introduced] by water [at His immersion. See Matt. 3:13] and [completed] by blood [at His crucifixion, John 19:17-37]. He did not come by the water only, but by the water and by the blood. And it is the Holy Spirit who gives testimony [at both of these events], because the Holy Spirit is [always] the truth. [See John 16:13].