Paul knew that the last enemy was death. Physical death is a curse of the Fall. With the new kingdom growth, the curse is being reversed and the final event will be the end of death.
Yes physical death is from the fall, death entered into creation through sin. It is because our physical body is mortal, and corruptible that it dies.
Romans 5:12 (KJV) Wherefore, as
by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned:
The curse of death is not being removed for those who believe, death has been removed for them. It is only our mortal, corruptible body that dies. Our body is the outward shell that contains us. From the fall our body is appointed to grow old, or sick and die. Just because our body dies does not mean that which is within our body, our spirit/soul dies.
If believers do not continue to live after our body dies then Christ would not have said the life we receive when we live and believe in Him will NEVER die. Christ gave us this assurance after the death of Lazarus. Then to prove their is still life after death for whosoever believes in Him, He raised Lazarus from the dead.
For believers the curse of death is gone through Spiritual life we receive when we are born again. When the Holy Spirit enters in, He becomes one with our spirit (mind, heart, will, emotion), and this part of believers never dies. In death we become as the angels of heaven, spiritual body. These verses aren't speaking of the bodily resurrection of every human on the last day. They speak of the resurrection of our spirit, through the Spirit in us, going to heaven as spiritual body after the death or our mortal, physical body of flesh & blood.
Matthew 22:30 (KJV) For
in the resurrection they neither marry, nor are given in marriage, but are
as the angels of God in heaven.
Luke 20:36 (KJV) Neither can they die any more: for they are equal unto the angels; and are the children of God, being the children of the resurrection.
Luke 20:37-39 (KJV) Now that the dead are raised, even Moses shewed at the bush, when he calleth the Lord the God of Abraham, and the God of Isaac, and the God of Jacob.
For he is not a God of the dead, but of the living: for all live unto him. Then certain of the scribes answering said, Master, thou hast well said.
1 Corinthians 15:12-14 (KJV) Now if Christ be preached that he rose from the dead, how say some among you that there is no resurrection of the dead? But
if there be no resurrection of the dead, then is Christ not risen: And if Christ be not risen, then
is our preaching vain, and your faith
is also vain.
1 Corinthians 15:16-18 (KJV) For if the dead rise not, then is not Christ raised: And if Christ be not raised, your faith
is vain; ye are yet in your sins. Then they also which are fallen asleep in Christ are perished.
1 Corinthians 15:22 (KJV) For
as in Adam all die, even so in Christ shall all be made alive.
1 Corinthians 15:35 (KJV) But some
man will say,
How are the dead raised up? and with what body do they come?
1 Corinthians 15:37-38 (KJV) And
that which thou sowest, thou sowest not that body that shall be, but bare grain, it may chance of wheat, or of some other
grain: But
God giveth it a body as it hath pleased him, and to every seed his own body.
1 Corinthians 15:44 (KJV) It is
sown a natural body; it is raised a spiritual body. There is a natural body, and there is a spiritual body.
1 Corinthians 15:45-50 (KJV) And so it is written, The first man Adam was made a living soul;
the last Adam was made a quickening spirit.
Howbeit that was not first which is spiritual, but that which is natural; and afterward that which is spiritual. The first man
is of the earth, earthy: the second man
is the Lord from heaven. As
is the earthy, such
are they also that are earthy:
and as is the heavenly, such are they also that are heavenly. And as we have borne the image of the earthy, we shall also bear the image of the heavenly. Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption.
It is because flesh and blood cannot inherit the kingdom of God in heaven that our physical mortal body must die, and cannot go as a spiritual body to heaven after death. When our mortal, corruptible body is raised and made immortal and incorruptible when Christ comes again on the last day when the final trumpet sounds, then ALL death will be defeated. That's when the last enemy (physical death) is swallowed up in victory, and there will be no more sting of the grave. Once our body is changed to immortal and incorruptible to join again with our eternal spirit, we will be whole again and fit for everlasting life on the new earth, to be with Christ throughout eternity.