In Scientology, we believe that you have lived before and that you will live again. The spirit, which is you, is immortal and you are not your body. You as an individual are an immortal spiritual being and simply put, you have lived before and will live again, lifetime after lifetime. In Scientology, these past existences are simply referred to as past lives.(as reported at MSN News)
Christianity rejects Scientology, and these doctrines of man. The Bible is the Christian's source of authority when it comes to the nature of man.
1. Reincarnation is False
The Christian doctrine of man is that man lives once, dies once, and will be raised on the day of judgment.
Scripture teaches that man has one life on earth, and after that the judgment:
Hebrews 9:27 And as it is appointed unto men once to die, but after this the judgment:
Scripture teaches also that the resurrection is general:
Acts 24:15 And have hope toward God, which they themselves also allow, that there shall be a resurrection of the dead, both of the just and unjust.
Although the resurrection is general, there will be a division - some will be raised to life, other will be raised to the second death: hell.
John 5:29 And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation.
2. Our Body is a Part of Us
As noted above, we await a bodily resurrection. Although we will have the same body, it will be changed. The mortal body we have now will be changed into an immortal body.
I Corinthians 15:35-44
35 But some man will say, How are the dead raised up? and with what body do they come? 36 Thou fool, that which thou sowest is not quickened, except it die: 37 And that which thou sowest, thou sowest not that body that shall be, but bare grain, it may chance of wheat, or of some other grain: 38 But God giveth it a body as it hath pleased him, and to every seed his own body. 39 All flesh is not the same flesh: but there is one kind of flesh of men, another flesh of beasts, another of fishes, and another of birds. 40 There are also celestial bodies, and bodies terrestrial: but the glory of the celestial is one, and the glory of the terrestrial is another. 41 There is one glory of the sun, and another glory of the moon, and another glory of the stars: for one star differeth from another star in glory. 42 So also is the resurrection of the dead. It is sown in corruption; it is raised in incorruption: 43 It is sown in dishonour; it is raised in glory: it is sown in weakness; it is raised in power: 44 It is sown a natural body; it is raised a spiritual body. There is a natural body, and there is a spiritual body.
We can also see that our bodies are a part of us from other places in Scripture, such as the following:
1 Thessalonians 5:23 And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ.
Thus, God told Adam:
Genesis 3:19 In the sweat of thy face shalt thou eat bread, till thou return unto the ground; for out of it wast thou taken: for dust thou art, and unto dust shalt thou return.
3. Our Spirits are Immortal in a Limited Sense, but are not eternal.
Men come into being. They are not eternal beings. Thus, Jesus said he was before Abraham.
John 8:58 Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am.
Furthermore, although our souls will never cease to exist, if we do not now repent and trust in Christ, there will come a time when both our body and soul will perish (eternally) in hell.
Matthew 10:28 And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell.
We reject the errors of Scientology, because they are contrary to the revealed word of God, our Creator and Redeemer. If one follows Scientology, one will eventually discover its errors. Man does not have an infinite number of lives to "get it right" - this life is it.
Psalm 2:12 Kiss the Son, lest he be angry, and ye perish from the way, when his wrath is kindled but a little. Blessed are all they that put their trust in him.