Christ said you must be born again.....
.
Yes he did but he was telling Nicodemus that his flesh and blood corruptible body could not enter the kingdom; it had to be born again as an incorruptible body.
That doesn't happen until the last trump. Paul also said the same thing:
1Corinthians 15:
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.
[55] O death, where is thy sting? O grave, where is thy victory?
[56] The sting of death is sin; and the strength of sin is the law.
[57] But thanks be to God, which giveth us the victory through our Lord Jesus Christ.
[58] Therefore, my beloved brethren, be ye stedfast, unmoveable, always abounding in the work of the Lord, forasmuch as ye know that your labour is not in vain in the Lord.