1st John 2:6

3 And hereby we know that we know him, if we keep his commandments.

4 He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him;

5 but whoso keepeth his word, in him verily hath the love of God been perfected. Hereby we know that we are in him:

6 he that saith he abideth in him ought himself also to walk even as he walked.

7 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.

8 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.

9 He that saith he is in the light and hateth his brother, is in the darkness even until now.