1 John 3:14-16

3:14 We know that we have crossed over from death to life because we love our fellow Christians. The one who does not love remains in death. 3:15 Everyone who hates his fellow Christian is a murderer, and you know that no murderer has eternal life residing in him. 3:16 We have come to know love by this: that Jesus laid down his life for us; thus we ought to lay down our lives for our fellow Christians.

1 John 4:21

4:21 And the commandment we have from him is this: that the one who loves God should love his fellow Christian too.