The Disciples' Limited Understanding that Jesus was God in the Flesh: Do you think that Jesus' disciples understood that Jesus was God in the flesh? [John 1:41, Isaiah 9:6, Isaiah 7:14:8-9, John 16:12, John 20:28, Romans 10:9-11, 1 John 1:13, 1 John 2:22]. Believing in the Trinity: Do you have to believe in the Trinity to be saved?