God intends that man will live forever, and has shown this throughout the Bible from Genesis to Revelation.
When God created man, He told Adam, "…From any tree of the garden you may eat freely; but from the tree of the knowledge of good and evil you shall not eat, for in the day that you eat from it you shall surely die." (Genesis 2:16,17)
When Adam disobeyed that instruction, God cast him from the garden “… lest he stretch out his hand, and take also from the tree of life, and eat, and live forever.” (Genesis 3:22)
Some may read Psalm 90:10 and believe that people were only to live for 80 years. “The years of our life are seventy, or even by reason of strength eighty; yet their span is but toil and trouble.” This verse is declaring the fact that most people have died by 80. However, our bodies lose vitality and health because we are living under God’s wrath. “For we are brought to an end by your anger…all our days pass away under your wrath…” Psalm 90:7,9. In God’s kingdom on earth, God’s wrath will be past. “In the midst…was there the tree of life…and the leaves of the tree were for the healing of the nations. And there shall be no more curse…” Revelation 22:2,3.
God created mankind to live forever, as long as they obeyed God's command. Once Adam and Eve sinned, he and all the human race (sin was inherited from Adam) were made subject to sin and death. Jesus paid the penalty for original sin thereby becoming the ransom for father Adam and his children. Even before creating the earth, God foreknew Adam would sin and had already determined a plan of rescue. (1 Peter 1:19,20)
In God's Kingdom, when the "proper time" has come, all will be resurrected to live again, as is shown in:
1 Timothy 2:6 "[Christ Jesus] gave Himself as a ransom for all, the testimony borne at the proper time."
Acts 24:15 "…there shall certainly be a resurrection of both the righteous and the wicked."
Then, the original rule will apply, obey and live…disobey and die. (Ezekiel 18:20 "…the soul who sins will die.") However, everyone will again have the ability to obey, as they will no longer be deceived by Satan (Revelation 20:3) and their minds & bodies will have perfect health. (Isaiah 35)
In Christ’s Kingdom, God’s original intention for man to live forever will finally be realized. Revelation 21:4 says, "and He shall wipe away every tear from their eyes; and there shall no longer be any death; there shall no longer be any mourning, or crying, or pain; the first things have passed away."