This chapter deals with regeneration. Regeneration, on one hand, brings the divine life with the divine nature into us. On the other hand, regeneration terminates the evil nature of Satan in our flesh. In Gen. 3 Satan, the serpent, injected his nature into man's flesh. When the children of Israel sinned against God, they were bitten by serpents (Num. 21:4-9). God told Moses to lift up a bronze serpent on their behalf for God's judgment, that by looking upon that bronze serpent all might live. That was a type. Here, in this verse, the Lord Jesus applied that type to Himself, indicating that when He was in the flesh, He was in "the likeness of the flesh of sin" (Rom. 8:3), which likeness is equal to the form of the bronze serpent. The bronze serpent had the form of the serpent but was without the serpent's poison. Christ was made in "the likeness of the flesh of sin," but He did not participate in any way in the sin of the flesh (2 Cor. 5:21; Heb. 4:15). When He was lifted up in the flesh on the cross, by His death Satan, the old serpent, was dealt with (John 12:31-33; Heb. 2:14). This means that the serpentine nature within fallen man has been dealt with. When a man is regenerated with the divine life in Christ, his satanic nature is annulled. Because of this, in this portion of the Word, when the Lord revealed the matter of regeneration to Nicodemus, He specifically mentioned this point.
Nicodemus might have considered himself a moral and good man. But the Lord's word in this verse implied that regardless of how good Nicodemus might have been outwardly, he had the serpentine nature of Satan inwardly. As a descendant of Adam, he had been poisoned by the old serpent, and the serpent's nature was within him. He needed the Lord not only to be the Lamb of God to take away his sin (John 1:29) but also to be in the form of the serpent that his serpentine nature might be dealt with on the cross and that he might have eternal life. In the principle set forth in ch. 2, this is the changing of death into life.