In the book of Genesis, it is implied that Adam (and those after him) faced ultimate/permanent death if and only if they transgressed one or more of God's commandments (i.e. sinned).
• In Genesis, we read of Adam and Eve initially being created by God in a paradise—“the garden of Eden.” They were given an opportunity to sin, in disobeying God’s command to “not eat” of a particular fruit tree (for in doing so, they would intimately know sin/guilt), and Gen 2:17 — “in the day [Heb. “Yom”; i.e. time-period] that you eat from it you will surely die.”
The Old Testament both explicitly and implicitly teaches that God plans on raising all his righteous remnant (Israel) to eternal life. (By contrast, the evil are at best raised up for judgment and second death.)
• Example: It is taught in Job, Psalms, Hosea (very early OT writings).
• Example: It is taught in Daniel 12:2.
• Example: It is taught in Isaiah 25:8 & 26:19.
• In Genesis, humans face ultimate death if and only if they were sinners.
• The OT says the messiah will be resurrected.
• Jews expected it.
• The OT affirms God’s omnipotence and omnibenevolence.
Jesus proclaimed to humanity that ultimate death is just for sinners (the sinless won’t stay dead).
• Gospels: “Jesus said, ‘by me, be sin free unto eternal life.’”
• Paul: “Through Jesus, become sin-free unto life.”
• John the Baptist: “Through Jesus, get cleansing-life.”
Biblically, God would uniquely raise the sinless (i.e. ultimately destroy the wicked and preserve the righteous).
• The Bible says: God wants the righteous to live forever.
• Psalm 97:10 — “He preserves Godly.”
• Ps 145:20 — “He keeps [us] & destroys wicked.”