1 John 3,4, and 5

1 John 3
Verse 2 tells us that we can become like God. We cannot see that potential right now. But when the day of resurrection comes and we are in his presence, we will see him in his resurrected glory and see that we are resurrected in the same manner he is with all of the divine potential that children of God have to become like their heavenly parents.

Verse 4 gives a succinct definition of sin. It is the transgression of law. I think it helps to look at the laws of God in the same manner we look at other laws such as the law of gravity or other physical laws that govern the universe. We can use those laws to better our lives, or we can transgress them to our detriment. The laws of God are no different. We can use them to better our lives or we can transgress them which will bring negative consequences. The consequences are that we stunt our ability to grow and mature into what we were created to be. In a sense we are like plants who control their own growth. We can nourish the plant with nutrients and sunlight or neglect to feed it and stunt its growth so that it never reaches it full stature and blooms in it's full glory.

The JST makes an important correction in verses 6-9. Rather than saying that people who have been born again "cannot sin," Joseph Smith used "continue in sin" which makes much more sense. Verse 11 is always the message of John. You can see why he was called the beloved.

1 John 4
This is one of my favorite chapters and one of the most beautiful in all of scripture. It explains the relationship between loving each other and loving God. To highlight what he says:

God is love and if we love others, God can dwell in us and the way we know if He dwells in us is through the Holy Ghost.

If we do not love, we cannot know Him. And in loving God, we come to realize how much He loved us to begin with.

Love is of God; through our love we are born of God, and if we love God and are born of Him, we can know Him.

The greatest manifestation of His love for us was His sending his Son.

"There is no fear in love; but perfect love casteth out fear. And as it says in the beginning of Chapter 5, if we love him, it is natural for us to want to keep the commandments.

1 John 5
The words "and these three are one" were not in the original Greek manuscripts but added later by the translators. The Father, Son and Holy Ghost are one in purpose, but are distinctly separate members of the Godhead.

Water, blood and the Spirit are the three elements of our physical birth into our families of this world, and they are the three elements of our spiritual birth into God's family. With our physical birth, it is necessary to have the water of the womb, the issue of blood, and our spirits entering our bodies at some point prior. With our spiritual birth, we come forth in the same manner, out of the waters of baptism, the blood of Christ cleanses us from sin, and the Spirit confirms and ratifies the act.

John tells us he has written what he has so we can believe and know the Savior, that there is eternal life, that God hears us and will answer our prayers. Then he closes this epistle by saying he knows that "the Son of God is come, and hath given us understanding, and that we may know him that is true, and we are in him that is true, even in his son Jesus Christ."