The Bible presents Jesus as being fully God and fully man in one person. Theologians call this doctrine the hypostatic union. Two complete natures are united in one person.
- Jesus is God the Son.
- Jesus was always God.
- Jesus became human.
When John wrote his first epistle (probably between A.D. 85 and 95), a false teaching was circulating in the church, which claimed that Jesus only seemed to have a physical body. This heresy became known as docetism. (The word "docetism" comes from the Greek word dokeo, shich means "to seem" or "to appear to be.") This false teaching about Jesus was what led John to write, "Every spirit that acknowledges that Jesus Christ has come in the flesh is from God, but every spirit that does not acknowledge Jesus is not from God. This is the spirit of antichrist" (1 John 4:2-3; cf. 2 John 7). John understood that to deny that Jesus had come in the flesh was to deny something at the very heart of Christianity (Wayne Grudem, Systematic Theology, p. 540).