In Matthew 22:31-32, Jesus proclaimed that God was not the God of the dead but the living, identifying Abraham, Isaac, and Jacob, who were physically dead and obviously in their graves. Paul, talking to people who were physically alive, proclaims that before they received the gift of God's Spirit, they were stone dead in their sins (Ephesians 2:1). In Luke 9:60, Jesus referred to people who were physically alive as dead. After Lazarus had died, Jesus had to reassure Martha that He was the Resurrection and the Life (John 11:25). Everyone is appointed once to die physically (Hebrews 9:27), but Jesus died to save us from the second death (or spiritual eternal death). After the Millennium, the rest of the dead will be resurrected and given an opportunity to accept Christ and live eternally. Sadly, some will reject this opportunity and perish in the Lake of Fire. In God's perspective, those who have the Holy Spirit (the mind of Christ) dwelling within are perpetually alive, while those who do not have the spirit of Christ are dead. Thankfully, those who died having God's spirit, will be resurrected to eternal life as part of His family.