If a person claiming to be a prophet acknowledges that Jesus Christ came in a real body, that person has the Spirit of God. But if someone claims to be a prophet and does not acknowledge the truth about Jesus, that person is not from God
I John 4:2-3
People were acknowledging the deity of Jesus quite readily in the first century. No one had any doubts about that. The things that Jesus accomplished could only be the work of God. What people just could not believe were his claims of humanity! Platonic thought was so strong in that time. It was common knowledge that God and human don’t mix. The spirit is good the flesh is not. Therefore Jesus could not be a for real flesh and blood human. John does his best to counter any story that minimizes or denies Jesus humanity. Any one who talks like that, John says, is nothing but bad news. How times have changed. Now, in our sophisticated modern world virtually everyone is willing to acknowledge the humanity of Jesus, but for sure not his deity.
