1 John 2:3-11 NIV
We know that we have come to know him if we keep his commands. Whoever says, “I know him,” but does not do what he commands is a liar, and the truth is not in that person. But if anyone obeys his word, love for God is truly made complete in them. This is how we know we are in him: Whoever claims to live in him must live as Jesus did.
Dear friends, I am not writing you a new command but an old one, which you have had since the beginning. This old command is the message you have heard. Yet I am writing you a new command; its truth is seen in him and in you, because the darkness is passing and the true light is already shining.
Anyone who claims to be in the light but hates a brother or sister is still in the darkness. Anyone who loves their brother and sister lives in the light, and there is nothing in them to make them stumble. But anyone who hates a brother or sister is in the darkness and walks around in the darkness. They do not know where they are going, because the darkness has blinded them.
NIV: New International Version