This war of Spirit and Flesh is first ostensibly declared in the words of Gen. vi. 3. This passage indicates the moral reaction of God's Spirit against the world's corruption, and the protest which in the darkest periods of human depravity He has maintained. God had allowed men to do despite to His good Spirit. But it cannot always be so. A time comes when, outraged and defied, He withdraws His influence from men and from communities; and the Flesh bears them along to swift destruction. So it was in the world before the Flood. So largely amongst later heathen peoples, when God "suffered all nations to walk in their own ways." Even the Mosaic law had proved rather a substitute than a medium for the free action of the Spirit of God on men. "The law was spiritual," but "weak through the flesh." It denounced the guilt which it was powerless to avert. With the advent of Christ all this is changed. The Spirit of God is now, for the first time, sent forth in His proper character and His full energy. At last His victory draws near. He comes as the Spirit of Christ and the Father, "_poured out_ upon all flesh." "A new heart will I give you, and a new spirit will I put within you. I will put My Spirit within you" (Ezek. xxxvi. 25-27): this was the great hope of prophecy; and it is realised. The Spirit of God's Son regenerates the human heart, subdues the flesh, and establishes the communion of God with men. The reign of the Spirit on earth was the immediate purpose of the manifestation of Jesus Christ. But what does Paul really mean by "the flesh?" It includes everything that is not "of the Spirit." It signifies the entire potency of sin. It is the contra-spiritual, the undivine in man. Its "works," as we find in vv. 20, 21, are not bodily vices only, but include every form of moral debasement and aberration. _Flesh_ in the Apostle's vocabulary follows the term _spirit_, and deepens and enlarges its meaning precisely as the latter does. Where _spirit_ denotes the supersensible in man, _flesh_ is the sensible, the bodily nature as such. When _spirit_ rises into the supernatural and superhuman, _flesh_ becomes the natural, the human by consequence. When _spirit_ receives its highest signification, denoting the holy Effluence of God, His personal presence in the world, _flesh_ sinks to its lowest and represents unrenewed nature, the evil principle oppugnant and alien to God. It is identical with _sin_. But in this profound moral significance the term is more than a figure. Under its use _the body_ is marked out, not indeed as the cause, but as the instrument, the vehicle of sin. Sin has incorporated itself with our organic life, and extends its empire over the material world. When the Apostle speaks of "the body of sin" and "of death," and bids us "mortify the deeds of the body" and "the members which are upon the earth,"[141] his expressions are not to be resolved into metaphors.