The reading is from St. John's First Universal Letter 2:7-17

Brethren, I am writing you no new commandment, but an old commandment which you had from the beginning; the old commandment is the word which you have heard. Yet I am writing you a new commandment, which is true in him and in you, because the darkness is passing away and the true light is already shining. He who says he is in the light and hates his brother is in the darkness still. He who loves his brother abides in the light, and in it there is no cause for stumbling. But he who hates his brother is in the darkness and walks in the darkness, and does not know where he is going, because the darkness has blinded his eyes. I am writing to you, little children, because your sins are forgiven for his sake. I am writing to you, fathers, because you know him who is from the beginning. I am writing to you, young men, because you have overcome the evil one. I write to you, children, because you know the Father. I write to you, fathers, because you know him who is from the beginning. I write to you, young men, because you are strong, and the word of God abides in you, and you have overcome the evil one. Do not love the world or the things in the world. If any one loves the world, love for the Father is not in him. For all that is in the world, the lust of the flesh and the lust of the eyes and the pride of life, is not of the Father but is of the world. And the world passes away, and the lust of it; but he who does the will of God abides for ever.