1 John 2:5-10

but whoso keepeth his word, in him verily hath the love of God been perfected. Hereby we know that we are in him: he that saith he abideth in him ought himself also to walk even as he walked. Beloved, no new commandment write I unto you, but an old commandment which ye had from the beginning: the old commandment is the word which ye heard. Again, a new commandment write I unto you, which thing is true in him and in you; because the darkness is passing away, and the true light already shineth. He that saith he is in the light and hateth his brother, is in the darkness even until now. He that loveth his brother abideth in the light, and there is no occasion of stumbling in him.