A person can only show repentance while alive. The soul does not live on after death (or is immortal) as the churches of Christendom have taught, for Ezekiel 18 says that "the soul that sinneth, it shall die."(Ez 18:4, KJV) The soul is us with all our desires, for at Deuteronomy 12, it says: "When the Lord thy God shall enlarge thy border, as he hath promised thee, and thou shalt say, I will eat flesh, because thy soul longeth to eat flesh, thou mayest eat flesh, whatsoever thy soul lustest after."(Deut 12:20, KJV)
And when our Creator, Jehovah God, made Adam, the Genesis account says: "And the Lord God formed man out of the dust of the ground, and breathed into his nostrils the breath of life; and man became (not possess) a living soul."(Gen 2:7, KJV)
And the apostle Paul confirmed this, saying: "And so it is written, The first man Adam was made a living soul."(1 Cor 15:45, KJV) The word soul comes from the Hebrew word ne´phesh that evidently comes from a root meaning “breathe” and in a literal sense ne´phesh could be rendered as “a breather.”
Hence, when a person has died, he or she ceases to exist, for Ecclesiastes says: "For the living know that they shall die: but the dead know not anything, neither have they any more a reward: for the memory of them is forgotten."(Ecc 9:5, KJV) Furthermore, the Psalmist wrote of humans who have died, that "his breath goeth forth, he returneth to his earth; in that very day his thoughts perish."(Ps 146:4, KJV)
Thus, for a person to be given another opportunity after death, they would have to be resurrected from death. That is why Jesus said to the Jews: "Do not marvel at this, because the hour is coming in which all those in the memorial tombs will hear his voice and come out, those who did good things to a resurrection of life, those who practiced vile things to a resurrection of judgment."(John 5:28, 29)
Thus, many of the billions that have died over the course of 6,000 years of human history will be resurrected during Jesus "thousand year" reign in the near future to be given an opportunity to please Jehovah God and live forever on an earthly paradise.(Matt 5:5)
Their being given everlasting life will depend on their faithful and loving works after their resurrection, not when they were alive the 1st time. These paid the penalty for their sins during the 1st time they were alive by dying.(Rom 6:23)
That is why Jesus said that "those who did good things" after their resurrection will receive a "resurrection of life" whereas those who "practiced vile things things to a resurrection of (adverse) judgment" or everlasting death. And that is why there is the expression "second death" (also called "the lake of fire", Rev 20:14), for the second time anyone dies, these are forever dead.
The evil-doer that asked Jesus to remember him when he ' got into his kingdom' (Luke 23:42) will be resurrected for the opportunity to live on the paradise earth that Jehovah originally purposed when he created Adam and Eve.(Gen 1:31; 2:9) Jesus told the evil-doer: "Truly I tell you today, You will be with me in Paradise."(Luke 23:43)