'So also it is written, "The first man Adam became a living soul." The last Adam was a life-giving spirit.'
He then illustrates this from history and Scripture. 'The first Adam became a living soul' (Genesis 2:7). When man was first created God breathed into him and he became a living being with a body of flesh, and he passed on life to those who followed him. All who were produced from him and his seed, owed all they were to him, and were by nature like him. He was a 'living soul', a body with life breathed in by God.
But in contrast the last Adam is a life-giving spirit, a Spirit Who in essence has spiritual life in Himself which He can dispense to others. Through what He was, and now is through His resurrection, Jesus not only had life in spiritual form but was also a potential giver of that life. All was totally different. As Adam began the old creation, and passed on earthly life to his children, a life he had received from God, so Christ, the last Adam, begins the new creation, and gives spiritual life to His own, a life which comes from Himself and from God. And they too become like Him (1 John 3:2).
We note that Jesus is the last Adam, not the second. Jesus Christ is the ultimate, the final life-giver. There can never be another. A third is not a possibility. No other will be necessary. He has fulfilled all that God had intended in Adam, and is the beginning of the new humanity.
It would, however, be a mistake to think that it was the resurrection which made Christ a life-giving Spirit and that He had not been so before. What it did do was reveal Him as a life-giving Spirit to those who were dead in sin. Prior to that He could give life, for ‘the Son has life in Himself --- and makes alive whom He will' (John 5:21; John 5:26). But nevertheless He also declared Himself to be the One Who would give final resurrection life (John 5:28-29). So all life is in His hands, both that given while He was still alive, and that which is in the future. And the life Jesus gives includes finally the resurrection of the body, for only so is the full restoration of the creation seen to occur. And that was only possible because He would suffer for our sins and rise again. From the very beginning in Him was life and the life was the light of men (John 1:4) and it was from Him that Adam received his life (John 1:3-4). And He could therefore confidently declare 'I am the Life' (John 14:6; John 11:35). The giver of life to Adam. The source of life for His own. Yet it will be through the resurrection that that fact will be especially manifested in the raising of men to a perfect life so that He could declare ‘I am the resurrection and the life' (John 11:35). So Jesus, John and Paul agree together.