1 John 2:5-10

But whoever habitually keeps His word and obeys His precepts [and treasures His message in its entirety], in him the love of God has truly been perfected [it is completed and has reached maturity]. By this we know [for certain] that we are in Him: whoever says he lives in Christ [that is, whoever says he has accepted Him as God and Savior] ought [as a moral obligation] to walk and conduct himself just as He walked and conducted Himself. Beloved, I am not writing a new commandment to you, but an old commandment which you have had from the beginning; the old commandment is the message which you have heard [before from us]. [John 13:34, 35] On the other hand, I am writing a new commandment to you, which is true and realized in Christ and in you, because the darkness [of moral blindness] is clearing away and the true Light [the revelation of God in Christ] is already shining. The one who says he is in the Light [in consistent fellowship with Christ] and yet habitually hates (works against) his brother [in Christ] is in the darkness until now. The one who loves and unselfishly seeks the best for his [believing] brother lives in the Light, and in him there is no occasion for stumbling or offense [he does not hurt the cause of Christ or lead others to sin].