1 John 2:7-11 (NRSV)
7 Beloved, I am writing you no new commandment, but an old commandment that you have had from the beginning; the old commandment is the word that you have heard. 8 Yet I am writing you a new commandment that is true in him and in you, because the darkness is passing away and the true light is already shining. 9 Whoever says, “I am in the light,” while hating a brother or sister, is still in the darkness. 10 Whoever loves a brother or sister lives in the light, and in such a person there is no cause for stumbling. 11 But whoever hates another believer is in the darkness, walks in the darkness, and does not know the way to go, because the darkness has brought on blindness.