Where are these Scriptural proofs?
Those who are in Christ have been predestinated unto the adoption.
Ephesians 1:5 Having predestinated us unto the adoption of children by Jesus Christ to himself, according to the good pleasure of his will,
What's the adoption?
Romans 8:23 And not only they, but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves,
waiting for the adoption, to wit, the redemption of our body.
The adoption is the redemption of the body. It is when we will be finally conformed to the image of Christ. It's a future promise to those in Christ.
1 Corinthians 15
49 And as we have borne the image of the earthy,
we shall also bear the image of the heavenly.
50 Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption.
51 Behold, I shew you a mystery; We shall not all sleep, but
we shall all be changed,
52 In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and
we shall be changed.
53
For this corruptible must put on incorruption, and this mortal must put on immortality.
54 So when this corruptible shall have put on incorruption, and this mortal shall have put on immortality, then shall be brought to pass the saying that is written, Death is swallowed up in victory.