St John captured the essence of teaching from final conversations before Jesus of Nazareth was crucified. In Gospel of John (ch 8) the message centres on truthful speech in contrast to a natural tendency to lie because a dark spirit with immense influence over humans is by nature a liar and a murderer from the beginning. So lies and murderous hatred go hand in hand and come from this dark spirit. This starkly contrasts with the truthfulness and love Jesus knew was in The Father, who people call God but do not take after while they are hating Jesus. This message is reflected in teachings of other Apostles such as Paul'sEpistle to the Ephesians who applied it to the growing body of believers.
