Christ gives you a 'robe of righteousness', but doesnt make anyone 'immortal' or give the gift of eternal life till after the resurrection, which is bodily and only then are we changed. Christ will resurrect and this means recreate dust like He did with the blind man, and in this case the righteous dead, or "dead in Christ", and breathe into them the breath of eternal life, and they will be raised up into the clouds along with the living saints, and taken to Heaven.
When Jesus called Lazarus from the tomb, we see what it means to be in the grave, or dead, and there is nothing 'immortal'.
John 11:43-44
43 And when he thus had spoken, he cried with a loud voice, Lazarus, come forth.
44 And he that was dead came forth, bound hand and foot with graveclothes: and his face was bound about with a napkin. Jesus saith unto them, Loose him, and let him go.
Nothing at all is stated about what transpired during those four days in which Lazarus was dead. Christ made no statement, neither did Martha or even Lazarus himself. The fact, of course, is that there was nothing to report about what happened after he died, no bright lights or gentle clouds or about the realm of the dead, simply because he had experienced the sleep of death which is a state of absolute silence and oblivion. Lazarus was not immortal, and had no consciousness or entity with his mind or ability to think, continue, he was just in the grave.
But Lazarus died before Christ defeated sin and death. He did not have the Holy Spirit to give him eternal/everlasting spiritual life because Christ had not yet sent His Spirit to be within us, and none could go to heaven until after the resurrection of Christ. What is true of all who died in faith before the first advent of Christ is that if they physically died in faith, the parable of Lazarus & the rich man shows the place of the dead for the righteous in the earth was separate from the place for the unrighteous dead, and this was called Abraham's bosom in the parable. Lazarus was called up from the physically dead to be physically alive again, not forever, but to die again. That to prove Christ has power to give life to the dead.
Old testament faithful saints after physical death would be supernaturally spiritually alive through Christ's Spirit after Christ resurrected from the dead and before ascending to heaven first descended into the lower parts of the earth, called Abraham's bosom, to set the captives of death free.
John 3:13 (KJV) And no man hath ascended up to heaven, but he that came down from heaven, even the Son of man which is in heaven.
Ephesians 4:8-10 (KJV) Wherefore he saith, When he ascended up on high, he led captivity captive, and gave gifts unto men. (Now that he ascended, what is it but that he also descended first into the lower parts of the earth? He that descended is the same also that ascended up far above all heavens, that he might fill all things.)