Summary: There are many Christians who don't understand what happens to them or their body after they die.
The questions most often asked after reading the following verses are about what happens to the physical body and spirit at the moment of death.
"But someone will ask, "How are the dead raised? With what kind of body do they come?" You foolish person! What you sow does not come to life unless it dies. And what you sow is not the body that is to be, but a bare kernel, perhaps of wheat or of some other grain. But God gives it a body as he has chosen, and to each kind of seed its own body. For not all flesh is the same, but there is one kind for humans, another for animals, another for birds, and another for fish. There are heavenly bodies and earthly bodies, but the glory of the heavenly is of one kind, and the glory of the earthly is of another. There is one glory of the sun, and another glory of the moon, and another glory of the stars; for star differs from star in glory. So is it with the resurrection of the dead. What is sown is perishable; what is raised is imperishable. It is sown in dishonor; it is raised in glory. It is sown in weakness; it is raised in power. It is sown a natural body; it is raised a spiritual body. If there is a natural body, there is also a spiritual body. Thus it is written, "The first man Adam became a living being"; the last Adam became a life-giving spirit. But it is not the spiritual that is first but the natural, and then the spiritual. The first man was from the earth, a man of dust; the second man is from heaven. As was the man of dust, so also are those who are of the dust, and as is the man of heaven, so also are those who are of heaven. Just as we have borne the image of the man of dust, we shall also bear the image of the man of heaven." (1 Cor 15:35-49 ESV)
There are five common questions:
1. "When I die will I be asleep in the grave, or will just my body lay in the grave and my soul is in Heaven?" (see 1 Thess 4:14; see 2 Cor 5:8; Luke 23:43; Phil 1:23).
2. "When I die will my soul reunite with my body when Jesus returns because I must appear before the judgment seat of Christ and receive what is due for what I have done?" (see 2 Cor 5:10 ESV)
3. "Since Jesus says I will get a new body, why do I need to be reunited with the old body?
4. “How would resurrection work if my body was cremated or has decomposed into nothing?"
5. “Because Jesus was raised in the same body He had before He died and His resurrection, then it must be the pattern for all Christians, so won’t my resurrection follow suit, and I will be raised with the same body? (see Luke 24:1-6; John 20:25, 27; Phil 3:20-21; 1 Cor 15:49).
"But if there is no resurrection of the dead, then not even Christ has been raised." (1 Cor 15:13-14 ESV)
"An hour is coming, in which all who are in the tombs will hear His voice, and will come forth; those who did the good deeds to a resurrection of life, those who committed the evil deeds to a resurrection of judgment" (John 5:28-29).
The word "resurrection" (Gk: 'anastasis' (an-as’-tas-is) denotes a raising up or rising. The word "dead" (Gk: 'nekros') is sometimes used for the death of the body but its most frequent sense is the actual spiritual condition of a person who is not Born-Again (see Matt 8:22, 10:8, 11;5; Luke 7:22, 60, 15:24; John 5:25; Rom 6:11,13; Eph 2:1,5; 5:14; Phil 3:11; Col 2:13; Rev 3:1)[see Vines and Thayers].
"I tell you this, brothers: flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable. Behold! I tell you a mystery. We shall not all sleep, but we shall all be changed, in a moment, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, and the dead will be raised imperishable, and we shall be changed. For this perishable body must put on the imperishable, and this mortal body must put on immortality. When the perishable puts on the imperishable, and the mortal puts on immortality, then shall come to pass the saying that is written: "Death is swallowed up in victory." "O death, where is your victory? O death, where is your sting?" (1 Cor 15:50-55 ESV)
The Bible does not explicitly say that the resurrected body is a reanimated or recreated old body of flesh that God will somehow put together the cremated ashes or powdered dust of a decomposed earthly body and then return it to the Born-Again Christian at the Resurrection.