A comment posted on this article on Conditional Immortality :
NATURAL IMMORTALITY: Is It Christian Doctrine?
Could someone explain exactly what our Lord meant when he promised the dying thief that he would be with him in Paradise that same day?What did Paul mean when he said that he would rather go to be with Christ which was far better but for the sake of the Philippians he would have to stay? Phil. 1.23 The main thrust of New Testament teaching is opposed to natural immortality and the Christian’s hope is that he will receive a new body, Phil.3.21 and especially 1 Cor. 13, but these texts need some explaining.
Here are some articles that address these issuesThe Penitent Thief
This verse says that “to die is gain”, from which it is taught that the “gain” is going to heaven to be with the Lord. But whose gain? Christ’s or Paul’s? Most expositors seem to think it is Paul’s, but this would contradict the very spirit of this context. It would introduce a self-motive which was completely lacking in the Apostle’s mind here. Even if chapter three is remembered with its stress on the “prize of the high calling” (Phil.3:14), we must not assume that this is the only theme that is brought forward in this epistle. Paul has certainly avoided the spirit of Peter when he said “Behold, we have forsaken all, and followed Thee, what shall we have therefore?” (Mat.19:27)