What really set Christianity apart in the ancient world was the incarnation—the claim that the Most High God had himself entered into the realm of matter, taking on a physical body. In Gnosticism, the highest deity would have nothing to do with the material world. By contrast, the Christian message is that the transcendent God has broken into history as a baby born in Bethlehem. The incarnation is genuinely physical, happening at a particular time and in a particular geographical location.
In the days of the early church, this was Christianity’s greatest scandal. That’s why the apostles repeatedly stressed Christ’s body: that in him “all the fullness of the Deity lives in bodily form” (Col. 2:9), that he “’bore our sins’ in his body on the cross” (1 Pet. 2:24), that “we have been made holy through the sacrifice of the body of Jesus Christ” (Heb. 10:10). John even says the crucial test of orthodoxy is to affirm that Jesus has “come in the flesh” (1 John 4:2). When Jesus was executed on a Roman cross, we might say he ‘escaped’ from the material world, just as the Gnostics taught we should aspire to do. But what did he do next? He came back—in a bodily resurrection! To the ancient Greeks, that was not spiritual progress; it was regress. Who would want to come back to the body? The whole idea of a bodily resurrection was utter ‘foolishness to the Greeks’ (1 Cor. 1:23). Even Jesus’ disciples thought they were seeing a ghost—he had to assure them he was present bodily: “Look at my hands and my feet. It is I myself! Touch me and see; a ghost does not have flesh and bones as you see I have” (Luke 24:39).