But, if we live in the light [of righteousness] just like God [constantly] lives in the light [of righteousness], we can truly share a relationship with one another and [can know that] the blood of Jesus, God's Son, continues to cleanse [our spirits] from all of our sins.

But the person who obeys what His teaching requires, truly in this person love for God has been made complete. This is [another way] to be sure that we are in [fellowship with] Him:

My dearly loved ones, I am not writing to you about a new commandment, but about an old one. [It is the one] you had learned about from the beginning. [Note: This is the commandment to love one another (3:1: II John 5) which Jesus had taught his disciples during His earthly ministry. See Mark 12:31]. This old commandment is the word [of God] which you heard [previously].

Yet, I am [also] writing to you about a new commandment [Note: This commandment was to love one another as Jesus loved them. See John 13:34]; its truth is [being demonstrated] by Christ [perfectly] and [also] by you people [in a lesser measure], because the darkness [of sin] is passing away, and the real light [of righteousness] is already shining [in people's lives].

You people should continue [to practice] what you heard from the beginning [i.e., to love one another, See verses 7-11]. If you do, then you also will continue in [fellowship with] the Son, and with the Father.

[Now] this is the message that you people heard from the beginning [of Christ's ministry], that we should love one another [See Mark 12:31],

And this is His commandment: We should believe in the name of His Son Jesus Christ [i.e., the person of Christ], and love one another, just He has commanded us to do.

And God lives in the heart of the person who [continually] obeys His commands, and he lives in [fellowship with] God. And here is [another] way we know that God lives in our hearts: It is by [means of] the Holy Spirit, whom God gave to us. [See Rom. 8:9, 11; James 4:5; I Cor. 6:19].

Loved ones, we should have love for one another, because love comes from [the very nature of] God, and every person who [continually] loves [others] has been [spiritually] conceived by God [See 2:29; 3:9], and knows [he is in fellowship with] God.

Loved ones, if God loved us that much, we should also love one another.

No person has gazed upon God [at any time]; [but] if we love one another, God [continually] lives in our hearts, and His love is made complete within us.