They went out from us, but they didn't belong to us; for if they had belonged to us, they would have continued with us. But they left, that they might be revealed that none of them belong to us.

 The commandment to love was old in the sense that men had known of it for long; but it was new because in Jesus Christ love had reached a standard which it had never reached before and it was by that standard that men were bidden to love. 