Genesis 3:19

The last part of God's curse on Adam involves the brevity of physical life. To this point, death had been mentioned only as a threatened punishment for sin (Genesis 2:17), so it must be assumed that, as long as Adam and Eve remained sinless, they would not die. Paul writes in Romans 5:12, "Therefore, just as through one man sin entered the world, and death through sin, and thus death spread to all men, because all sinned."

God designed His wording of Adam's punishment to link mankind with the earth: He was created out of it, and when he died, he would return to it. His sin had removed him from the environs of the heavenly and forced him to dwell, labor, and die in the earthly. Yet even this has a silver lining:

And so it is written, "The first man Adam became a living being." The last Adam became a life-giving spirit. However, the spiritual is not first, but the natural, and afterward the spiritual. The first man was of the earth, made of dust; the second Man is the Lord from heaven. As was the man of dust, so also those who are made of dust; and as is the heavenly Man, so also are those who are heavenly. And as we have borne the image of the man of dust, we shall also bear the image of the heavenly Man. (I Corinthians 15:45-49)

The benefit of a physical body is that it can die! This may sound strange, but it is exactly this fact that makes man able to become immortal sons of God! Men can die and be resurrected, following the pattern set by Christ, receiving eternal life and the rewards of His Kingdom. It is our righteous living in the flesh through the grace of God that qualifies us for this glorious potential.

On the flip side, our physical nature also makes it possible for God to rid the universe of anyone unwilling to submit to Him. Unlike angels, men can be completely consumed in the Lake of Fire—totally destroyed for all eternity and unable to defile the holiness of God's Kingdom. Though God desires "all [to] come to repentance" (II Peter 3:9) and "all men to be saved" (I Timothy 2:4), He has this option should it be needed. Revelation 19:20 shows that it will indeed.