What the entire passage of Romans 5:12-19 is teaching us is that the effect of Jesus' obedience negated the effect of Adam's disobedience. The "original sin" imposed by Adam's sin was completely set aside by Jesus' obedience. So instead of "original sin" being imposed upon mankind at birth; rather it is "original grace" being imposed upon all mankind at birth. The spirits formed in man (Zech 12:1) are not dead in trespasses and sins, but rather are alive and well. And they remain alive until the individual commits trespasses and sins. It is only then and only due to his own trespasses and sins, not Adam's, that one's spirit becomes dead.
Thus the very first statement of that passage, namely verse 12, says death (spiritual death) spread to all men, not because Adam sinned but rather because they all sinned. The rest of the passage provides the details of just why that is.
What Adam passed onto man was disobedience, that is why it is by the obedience of one that many are made alive.
Adam covered his transgressions. Our first father sinned and our teachers, ( in the law) transgressed against God. ( all were taught by disobedience)
Job 31:33 If I covered my transgressions as
Adam, by hiding mine iniquity in my bosom:
Isaiah 43:27 Thy
first father hath
sinned, and thy teachers have transgressed against me.
Scripture continues, we were sometimes foolish and disobedient/deceived. ( under tutors until we escaped the elements of the world, God sending HIs Son to redeem them that were under the law, to receive adoption of sons.)
Christ made of a woman, found in fashion as a man, humbled Himself and became obedient unto the death, even the death of the cross, God highly exalts Him by this to give the name which is ABOVE every name, to confess that Jesus Christ is Lord to the glory of God the Father...
Galatians 4:2 But is under tutors and governors until the time appointed of the father.
3 Even so we, when we were children, were in bondage under the elements of the world:
4 But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law,
5 To redeem them that were under the law, that we might receive the adoption of sons.
Titus 3:3 For we ourselves also were sometimes foolish,
disobedient, deceived, serving divers lusts and pleasures, living in malice and envy, hateful, and hating one another.
Philippians 2:8 And being found in fashion as a man, he humbled himself, and became obedient unto death, even the death of the cross.
9 Wherefore God also hath highly exalted him, and given him a name which is above every name:
10 That at the name of Jesus every knee should bow, of things in heaven, and things in earth, and things under the earth;
11 And that every tongue should confess that Jesus Christ is Lord, to the glory of God the Father.
12 Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling.
Continuing, this is the just one suffering for sins ( all the sins of all that are in Adam, from birth or after, makes no difference, all is unbelief.) to bring us to God, put to death in the flesh, but quickened by the Spirit.
He preached to the spirits in prison ( the prison house) who were disobedient, ( seen in the flood) and the answer of a good conscience saves us towards God, which is the resurrection of Jesus Christ.
They who believe He is precious, but unto those who do not believe, they remain DISOBEDIENT ( ( IN ADAM)
They stumble at the Word, being DISOBEDIENT, whereunto they also were appointed...
1 Peter 3:18 For Christ also hath once suffered for sins, the just for the unjust, that he might bring us to God, being put to death in the flesh, but quickened by the Spirit:
19 By which also he went and preached unto the spirits in prison;
20 Which sometime were disobedient, when once the longsuffering of God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls were saved by water.
21 The like figure whereunto even baptism doth also now save us (not the putting away of the filth of the flesh, but the answer of a good conscience toward God,) by the resurrection of Jesus Christ:
22 Who is gone into heaven, and is on the right hand of God; angels and authorities and powers being made subject unto him.
1 Peter 2:7 Unto you therefore which believe he is precious: but unto them which be
disobedient, the stone which the builders disallowed, the same is made the head of the corner,
1 Peter 2:8 And a stone of stumbling, and a rock of offence, even to them which stumble at the word, being
disobedient: whereunto also they were appointed.
Romans 5:19 For as by
one man's
disobedience many were made sinners, so by the obedience of
one shall many be made righteous.
1 Corinthians 15:22 For as in
Adam all die, even so in Christ shall
all be made
alive.