1 Corinthians 15:21
"For since death came through a man, the resurrection of the dead comes also through a man."
Death (mortality, sicknesses, infirmity, eternal death, and misery in another world) would not have entered this world until Adam ate the first fruit of (rebellion) sin in the garden. The sense is, evidently, that in consequence of the sin of Adam all people die.
"Jesus said to her, 'I am the resurrection and the life. The one who believes in me will live, even though they die; and whoever lives by believing in me will never die. Do you believe this?'"
The resurrection through Jesus is the assurance that all who received Jesus shall never die again. Jesus death and resurrection was to restore man to life. An abundant life on earth as it is in Heaven. It is an eternal reward.
Adam brought death. Jesus brought life. When Jesus rose from the death, taking on the nature of a man to experience death. Return from the dead was the finished kingdom assignment & restored unity between God & man, as well as, taking dominion and subduing the earth (Genesis 1:26-28)
“But God released him from the horrors of death and raised him back to life, for death could not keep him in its grip.”