Jesus assured that it is from their graves that he will bring out the dead:
John 5:28 Do not be amazed at this, for the hour is coming in which all those in the memorial tombs will hear his voice 29 and come out, those who did good things to a resurrection of life, and those who practiced vile things to a resurrection of judgment.
That means that no dead person is still alive in some form, in some other place apart from where they were buried.
The physical body will be resurrected to life in the hour coming. Mankind shall all be physically resurrected to physical life, or to resurrection of damnation. Christ knowing, every human body is destined to die, just as Lazarus was physically dead. Martha, the sister of Lazarus, like you believed that her brother, now dead, would not live again until the last day. Listen carefully to what Christ says:
John 11:21-27 (KJV) Then said
Martha unto Jesus, Lord, if thou hadst been here, my brother had not died. But I know, that even now, whatsoever thou wilt ask of God, God will give it thee. Jesus saith unto her, Thy brother shall rise again. Martha saith unto him, I know that he shall rise again in the resurrection at the last day. Jesus said unto her, I am the resurrection, and the life: he that believeth in me, though he were dead, yet shall he live: And whosoever liveth and believeth in me shall never die. Believest thou this? She saith unto him, Yea, Lord: I believe that thou art the Christ, the Son of God, which should come into the world.
If there is not life after our physical body dies, Christ would not promise that whosoever lives and believes in Him SHALL NEVER DIE. There is no life in our physical body after death, as the death of Lazarus clearly shows. But Lazarus was raised to life again to prove Christ has power over death. The spirit that gave Lazarus' body physical life returned to him at the Lord's command. Christ was not commanding a corpse to live again; He was commanding the spirit of Lazarus to return life (spirit) to his body. And Lazarus came out of the tomb alive after physical death. Without a spirit in man there is no life, for it is the spirit that gives life to our flesh. Lazarus was raised to life again because death of his body die not mean death of his spirit. Man is made of body + spirit, and together they are a living soul. But when we are indwelt by the Holy Spirit from Christ, the spiritual life we receive from Him SHALL NEVER DIE.
John 6:63 (KJV) It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto you, they are spirit, and they are life.
When humans die their body returns to dust, while the spirit, giving life to the body, returns to God who gave it. Knowing this Christ prays to the Father, thanking Him for hearing His prayer that the people watching would know that the power He has over death comes from the Father, and to prove He was sent by the Father, the spirit returned to Lazarus, and all who witnessed this miracle saw the glory of God, and would believe in Him.
Ecclesiastes 12:7 (KJV) Then shall the dust return to the earth as it was: and the spirit shall return unto God who gave it.
John 11:38-44 (KJV) Jesus therefore again groaning in himself cometh to the grave. It was a cave, and a stone lay upon it. Jesus said, Take ye away the stone. Martha, the sister of him that was dead, saith unto him, Lord, by this time he stinketh: for he hath been
dead four days. Jesus saith unto her,
Said I not unto thee, that, if thou wouldest believe, thou shouldest see the glory of God? Then they took away the stone
from the place where the dead was laid.
And Jesus lifted up his eyes, and said, Father, I thank thee that thou hast heard me. And I knew that thou hearest me always: but because of the people which stand by I said it, that they may believe that thou hast sent me. And
when he thus had spoken, he cried with a loud voice, Lazarus, come forth. 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.
Before Christ left this earth, He promised to send His Spirit to be within whosoever believes in Him. He promises that His Spirit will never leave us, nor will He ever forsake us. The spiritual life believers receive through the Spirit in us SHALL NEVER DIE. The spirit that gives life to our physical body is indwelt by the Spirit from Christ, therefore the spirit in man, through the Holy Spirit SHALL NEVER DIE. The spirit of believers returns to the Father in heaven a spirit soul. Because where there is life there is a living soul, whether physical or spiritual.
John 14:16-17 (KJV) And
I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever;
Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you.