1 John 4:21

4:21 And the commandment we have from him is this: that ¹  the one who loves God should love his fellow Christian ²  too.

John 13:34

13:34 “I give you a new commandment – to love ³  one another. Just as I have loved you, you also are to love one another. ⁴ 

John 15:12

15:12 My commandment is this – to love one another just as I have loved you. ⁵ 

[4:21]  ¹ tn The ἵνα (Jina) clause in 4:21 could be giving (1) the purpose or (2) the result of the commandment mentioned in the first half of the verse, but if it does, the author nowhere specifies what the commandment consists of. It makes better sense to understand this ἵνα clause as (3) epexegetical to the pronoun ταύτην (tauthn) at the beginning of 4:21 and thus explaining what the commandment consists of: “that the one who loves God should love his brother also.”

[4:21]  ² tn See note on the phrase “fellow Christian” in 2:9.

[13:34]  ³ tn The ἵνα (Jina) clause gives the content of the commandment. This is indicated by a dash in the translation.

[13:34]  ⁴ sn The idea that love is a commandment is interesting. In the OT the ten commandments have a setting in the covenant between God and Israel at Sinai; they were the stipulations that Israel had to observe if the nation were to be God’s chosen people. In speaking of love as the new commandment for those whom Jesus had chosen as his own (John 13:1, 15:16) and as a mark by which they could be distinguished from others (13:35), John shows that he is thinking of this scene in covenant terminology. But note that the disciples are to love “Just as I have loved you” (13:34). The love Jesus has for his followers cannot be duplicated by them in one sense, because it effects their salvation, since he lays down his life for them: It is an act of love that gives life to people. But in another sense, they can follow his example (recall to the end, 13:1; also 1 John 3:16, 4:16 and the interpretation of Jesus’ washing of the disciples’ feet). In this way Jesus’ disciples are to love one another: They are to follow his example of sacrificial service to one another, to death if necessary.

[15:12]  ⁵ sn Now the reference to the commandments (plural) in 15:10 have been reduced to a singular commandment: The disciples are to love one another, just as Jesus has loved them. This is the ‘new commandment’ of John 13:34, and it is repeated in 15:17. The disciples’ love for one another is compared to Jesus’ love for them. How has Jesus shown his love for the disciples? This was illustrated in 13:1-20 in the washing of the disciples’ feet, introduced by the statement in 13:1 that Jesus loved them “to the end.” In context this constitutes a reference to Jesus’ self-sacrificial death on the cross on their behalf; the love they are to have for one another is so great that it must include a self-sacrificial willingness to die for one another if necessary. This is exactly what Jesus is discussing here, because he introduces the theme of his sacrificial death in the following verse. In John 10:18 and 14:31 Jesus spoke of his death on the cross as a commandment he had received from his Father, which also links the idea of commandment and love as they are linked here. One final note: It is not just the degree or intensity of the disciples’ love for one another that Jesus is referring to when he introduces by comparison his own death on the cross (that they must love one another enough to die for one another) but the very means of expressing that love: It is to express itself in self-sacrifice for one another, sacrifice up to the point of death, which is what Jesus himself did on the cross (cf. 1 John 3:16).