It is clear that all three aspects of love—for God, the world, and fellow believers—are equally essential in John’s Gospel

The command was new in that a new demonstration had been given of love, which the disciples were now bidden to emulate.

The new command enjoined men to preserve the same relationship with one another that Jesus had cultivated with them and mankind generally.

Having announced his departure, and having insisted that his disciples cannot now come with him (v. 33), Jesus begins to lay out what he expects of them while he is away.

The standard of comparison is Jesus’ love (cf. v. 1), just exemplified in the footwashing (cf. vv. 12–17); but since the footwashing points to his death (vv. 6–10), these same disciples but a few days later would begin to appreciate a standard of love they would explore throughout their pilgrimage

Its newness is bound up not only with the new standard (‘As I have loved you’) but with the new order it both mandates and exemplifies.

A new commandment I give unto you (with the purpose and scope) that ye love one another; even as (or, seeing that) I loved you, that ye (also) love one another.

Commands to love were already known in the sense of the highest devotion to God, but Jesus’ command that the disciples should love one another was new both in its scope and its motivation, which sprang from the love Jesus had for them.

The word love is used only twelve times in John 1–12, but in John 13–21 it is used forty-four times! It is a key word in Christ’s farewell sermon to His disciples, as well as a burden in His High Priestly Prayer (John 17:26).

The word new does not mean “new in time,” because love has been important to God’s people even from Old Testament times (see Lev. 19:18). It means “new in experience, fresh.” It is the opposite of “worn out.

What was new was that believers were to love each other as Jesus loved them

Jesus’ “new command” in 13:34–35, that his disciples love one another as he has loved them, takes its point of departure from the Mosaic commandments “Love the LORD your God with all your heart and with all your soul and with all your strength” (Deut. 6:5) and “Love your neighbor as yourself” (Lev. 19:18) (cf. Mark 12:28–33).

It is possible that “new commandment” also alludes to the new covenant established at the Last Supper that involved the people’s inner transformation through the Spirit (see Jer. 31:29–34; Ezek. 36:24–26; see commentary at 3:3–8 above).

Where the old commandment enjoined men to love their neighbors as themselves, the new urged them to love as Jesus had loved. The new was, in fact, more difficult than the old, but grace for its accomplishment was freely provided.

Love. Gr. agapaō; see on Matt. 5:43, 44. The command reads literally, “keep on loving.”

The new command is therefore not only the obligation of the new covenant community to respond to the God who has loved them and redeemed them by the oblation of his Son, and their response to his gracious election which constituted them his people, it is a privilege which, rightly lived out, proclaims the true God before a watching world

just as I have loved you Jesus inserts this phrase into the commandment from Lev 19:18. The new part of the commandment is that Jesus’ disciples are instructed to love other people the way Jesus loved them—serving them like a slave would, as He does in this scene, even to the point of laying down their lives for others.

The Greek word agapān, translated “to love,” implies “divine love,” for it denotes the self-giving love of God (3:16).

It is sacrificial love to the extent of giving one’s life for the welfare of others, just as Jesus did (15:12–13; 1 John 3:16; 4:7–12). Love and self-sacrifice are reciprocal actions. Jesus’ love for his followers is the ground on which they can love one another. It is essential to experience Jesus’ love before we love our fellow-beings.

It is new in two ways. It first focuses on one’s fellow believer rather than on one’s neighbor [EGT, ICC, NICNT2]. And second it is a love that is based on Jesus’ love for his disciples [Bar, My, NICNT2].

Followers of great teachers reflect the characteristics of their teachers. Love was one of the principal attributes of Jesus

A manifestation of this same kind of love by the disciples of Jesus would give evidence of their relationship and close association with their Master.

People would be able to recognize them as Jesus’ disciples by their mutual love. Knowing the truth about Jesus is vital, but so also is believers’ love for one another.

The indicator of a Christian is the way they treat others.

It is love that is the true evidence that we belong to Jesus Christ.

The church leader Tertullian (A.D. 155–220) quoted the pagans as saying of the Christians, “See how they love one another?” And how do we evidence that love? By doing what Jesus did: laying down our lives for the brethren (1 John 3:16). And the way to start is by getting down and washing one another’s feet in sacrificial service.

(1) There is a new focus. We are still to love our neighbor, but now a more intense love is to be directed toward “one another.” (2) There is a new standard. We are no longer to love others “as you love yourself,” but “as I [Jesus] have loved you.” Christ’s own committed, self-sacrificial and limitless love is the yardstick by which we are to measure our love for our Christian brothers and sisters. And (3) there is a new outcome. As the Christian community is infused by Christlike love, the world of lost humankind realizes that Jesus is real—and that we are His.

I like Bruce Corley’s statement in his article “Biblical Theology of the New Testament” in the hermeneutics book Foundations For Biblical Interpretation: “Christ’s people are characterized by the ethic of love, whereby the ‘is-ness’ of grace is linked to the ‘ought-ness’ of love through the work of the Spirit

It is the essence of life in God’s new community, for it is only by seeing the love shared among the believers will all people recognize them as Jesus’ followers (13:35)

‘by’ [AB, BAGD, Gdt, HTC, LN, NICNT2, NTC, WBC; KJV, NASB, NET, NIV, NJB, NRSV], ‘by means of, through’ [LN]. The sentence ‘By this everyone will know that you are my disciples if you have love among each other’ is translated ‘If you love each other, everyone will know that you are my disciples’ [CEV, similarly TEV], ‘All people will know that you are my followers if you love each other’ [NCV], ‘It is by your love for one another, that everyone will recognise you as my disciples’ [NJB], ‘Your love for each other will prove to the world that you are my disciples’ [NLT], ‘This is how all men will know that you are my disciples, because you have such love for one another’ [Ph], ‘If there is this love among you, then everyone will know that you are my disciples’ [REB]. This preposition indicates the means by which one event makes another event possible [LN]. It is used to denote the object to which something happens or in which something shows itself, or by which something is recognized [BAGD]. The phrase ‘by this’ indicates that this love was to be the distinguishing mark of Jesus’ disciples [NICNT1].

This was not the reason why they should love one another, but rather its outcome. People would be able to recognize them as Jesus’ disciples by their mutual love.

Knowing the truth about Jesus is vital, but so also is believers’ love for one another.