What does it mean that Jesus was the "second Adam"?

1 corinthians 15:45 is talking about Adam and Jesus, the last Adam.

Adam

• Adam was created by God and behold He saw that it was very good. He was created as "good", perfect and without sin.
• Adam was the originator of human race
• Eve was tempted and fell and Adam with him fell too
• Devil was given all power and glory of them(all kingdoms of the world) through the fall of Adam[luke.4:6]
• Adam and Eve were now fallen and sinful. They were spiritually dead[eph.2:1 & col.2:13].

Last Adam

• last Adam was created by God( power of the Highest shall overshadow Mary[luke.1:35]) in Mary's womb as sinless.
• one could interpret, that last Adam was the originator of new human race, new breed, through faith in Him by grace[eph.2:8].
• Devil fell( long period in between ) and tempted last Adam( eq. in the wilderness[matt.4:1] ), but He did not fell.
• Jesus, last Adam was given all power in heaven and in earth through the work of Jesus in Galvary[matt.28:18 & col.2:15]

The reason why I think this notion about Jesus being the last Adam is important, is that I got an idea that Jesus, the Christ is last Adam as Paul describes in 1 corinthians 15:45.

It came to my mind that Jesus was called the last Adam in the Bible, when I thought about the statement from a bishop of orthodox church of Finland that the starting point of orthodox perception of a human is the goodness of man. Then I thought about Adam before the fall and thought what it must have felt like to live then as perfect, sinless human. I maybe tried to go back to good old days before the fall and dreamed to be like that Adam, but now I realised that I don't have to identify myself to the Adam before the fall but to the last/second Adam. And I don't have to follow the first Adam before the fall, but last/second Adam who was as Adam was before the fall. That's why he is called last/second Adam, because he was as Adam was before the Fall; without sin in Him. If I would identify myself and would try to follow the first Adam before the fall, then it would be impossible for me or otherwise I would be living in my own strength, because Adam was tempted like I was, but failed, but now we have better Adam; last Adam, who as sinless, overcame all temptations and was saviour and redeemer for all man.

So the reason why I think this notion about Jesus being the last Adam is important is that Paul hold the Scriptures at the time including story of the genesis and especially the fall at least authentic. And Paul now out of the scriptures at the time, defined who Jesus was/is; the last Adam. But He is not only last Adam, because Bible defines Him by many other titles as well. So it is important, because Paul defines Jesus as a new originator of the human race, whom we can identify ourselves; the last Adam. It is a title which defines Jesus as "new originator" of "new breed" among human race. He is fully human, yet at the same state as Adam was before the fall; without sin.

Herein is our love made perfect, that we may have boldness in the day of judgment: because as he is, so are we in this world.[1 john.4:17(KJV)]

And now we are new breed; as he is, so are we (almost) in this world, through faith in Jesus by grace. Another question is, what apostle John meant by saying; as he is, so are we in this world? Maybe he meant that faithful are imitators of Christ, Christlike, christians.

If you have Dake's annotated reference bible you find there in page 174 of NT side a analysis titled as

"12 contrasts: Adam-Christ( rom.5)".

There Dake give 12 contrasts, where he compares Adam and Christ( last/second Adam).

From the first Adam we inherited death, or our sin nature, and seperation from God, But Christ came to reverse that and restore us to the state where we are no longer overcome by sin, but have control of our life through His crucifiction. Read Romans ch 6 or for an expanded version and excellent exposition, The Normal Christian Life, by Watchman Nee. This is simple but brilliant! Its online.

There are a few places where Jesus and Adam are mentioned together. Two note-worthy passages are in 1 Corinthians and Romans:

1 Corinthians 15:22 (NIV)
For as in Adam all die, so in Christ all will be made alive.

Romans 5:12-21 (NIV)
12 Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all people, because all sinned—

13 To be sure, sin was in the world before the law was given, but sin is not charged against anyone’s account where there is no law. 14 Nevertheless, death reigned from the time of Adam to the time of Moses, even over those who did not sin by breaking a command, as did Adam, who is a pattern of the one to come.

15 But the gift is not like the trespass. For if the many died by the trespass of the one man, how much more did God’s grace and the gift that came by the grace of the one man, Jesus Christ, overflow to the many! 16 Nor can the gift of God be compared with the result of one man’s sin: The judgment followed one sin and brought condemnation, but the gift followed many trespasses and brought justification. 17 For if, by the trespass of the one man, death reigned through that one man, how much more will those who receive God’s abundant provision of grace and of the gift of righteousness reign in life through the one man, Jesus Christ!

18 Consequently, just as one trespass resulted in condemnation for all people, so also one righteous act resulted in justification and life for all people. 19 For just as through the disobedience of the one man the many were made sinners, so also through the obedience of the one man the many will be made righteous.

20 The law was brought in so that the trespass might increase. But where sin increased, grace increased all the more, 21 so that, just as sin reigned in death, so also grace might reign through righteousness to bring eternal life through Jesus Christ our Lord.

The general gist of these passages is that where Adam brought sin, suffering, and death to our world, Jesus Christ brought grace, peace, and life to our world. In essence, Jesus had the opposite effect of Adam, but they were both the first of their kind and both hugely influenced the spiritual situation of the world. Hence, Jesus could be considered a "second Adam".

1 Cor. 15:22, 45

22 For as in Adam all die, even so in Christ all shall be made alive. . . .

45 And so it is written, "The first man Adam became a living being." The last Adam became a life-giving spirit.

The specific reference is to obedience; The first Adam was the father of all men through the Flesh and disobeyed, and through him all of his progeny learned disobedience and inherited death, whereas the 'second' or 'last' Adam becomes the father of all men through the Spirit, and was perfect in obedience. Through him, all his progeny learn to be obedient to the will of God and inherit life.

See also, related:

Romans 5:12-21 NIV

12 Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all men, because all sinned-- 13 for before the law was given, sin was in the world. But sin is not taken into account when there is no law. 14 Nevertheless, death reigned from the time of Adam to the time of Moses, even over those who did not sin by breaking a command, as did Adam, who was a pattern of the One to come.

15 But the gift is not like the trespass. For if the many died by the trespass of the one man, how much more did God's grace and the gift that came by the grace of the one man, Jesus Christ, overflow to the many! 16 Again, the gift of God is not like the result of the one man's sin: The judgment followed one sin and brought condemnation, but the gift followed many trespasses and brought justification.

17 For if, by the trespass of the one man, death reigned through that one man, how much more will those who receive God's abundant provision of grace and of the gift of righteousness reign in life through the one man, Jesus Christ. 18 Consequently, just as the result of one trespass was condemnation for all men, so also the result of one act of righteousness was justification that brings life for all men.

19 For just as through the disobedience of the one man the many were made sinners, so also through the obedience of the one man the many will be made righteous. 20 The law was added so that the trespass might increase. But where sin increased, grace increased all the more, 21 so that, just as sin reigned in death, so also grace might reign through righteousness to bring eternal life through Jesus Christ our Lord.

I believe 'The Second Adam' is an interpolation, i.e, a term that is not explicitly in the scripture like 'Trinity' but enjoys common usage because of its descriptive faculty.