The passage that he was incorrect in citing, and obtuse in translating, is actually appropriate. It's from chapter three of The First Epistle of John, however, and says the following:
11 For this is the message you have heard from the beginning, that we should love one another. 12 We must not be like Cain who was from the evil one and murdered his brother. And why did he murder him? Because his own deeds were evil and his brother’s righteous. 13 Do not be astonished, brothers and sisters,[a] that the world hates you. 14 We know that we have passed from death to life because we love one another. Whoever does not love abides in death. 15 All who hate a brother or sister[b] are murderers, and you know that murderers do not have eternal life abiding in them. 16 We know love by this, that he laid down his life for us—and we ought to lay down our lives for one another. 17 How does God’s love abide in anyone who has the world’s goods and sees a brother or sister[c] in need and yet refuses help?
18 Little children, let us love, not in word or speech, but in truth and action. 19 And by this we will know that we are from the truth and will reassure our hearts before him 20 whenever our hearts condemn us; for God is greater than our hearts, and he knows everything. 21 Beloved, if our hearts do not condemn us, we have boldness before God; 22 and we receive from him whatever we ask, because we obey his commandments and do what pleases him.
23 And this is his commandment, that we should believe in the name of his Son Jesus Christ and love one another, just as he has commanded us. 24 All who obey his commandments abide in him, and he abides in them. And by this we know that he abides in us, by the Spirit that he has given us.