And Jesus said unto him, Verily I say unto thee, Today shalt thou be with me in paradise. (Luke 23:43)
This verse is controversial as proponents of psychopannychism or thnetopsychism ("soul-sleep" and "soul-death," respectively—often labelled “mortalism”) argue that the punctuation in the KJV and other translations is wrong and instead it should be punctuated, “I say unto thee today, you will be with me in paradise,” that is, it refers to the time Jesus made the promise to the good thief, not that the good thief would, on that day, enter “paradise.”
One of the many problems with this perspective is that it would result in an inconsistency in how the author of Luke used σήμερον ("today"). As New Testament scholar Jerome Neyrey wrote:
[T]he climax of this scene is Jesus’ remark: “Today you will be with me in paradise” (23:43). According to Luke’s overall perspective, Jesus’ remark proclaims two things: (1) the man’s sin are forgiven, for sinners are excluded from paradise, and (b) the man is promised eschatological life: he will surely die on the cross, and paradise is not a place of death. Much scholarly discussion has been given to the meaning of “today” in Jesus’ remark, especially whether this refers to the final judgement after a long stay in some intermediate state. It is important to ask what Luke means by these words, rather than to speculate on what the historical Jesus could have meant by them. The Lukan understanding of them is accessible to us and we do well to concentrate on that.
Luke’s Gospel contains numerous examples of the proclamation of immediate salvation: the angels announce to the shepherd, “Today is born to you a Savior” (2:11); to the repentant Zacchaeus Jesus proclaims, “Today salvation has come to this house” (19:9). “Today” saying prophecies are fulfilled (4:21), “today” sins are forgiven (5:26), and “today” demons are cast out (13:32). Luke’s Gospel, then, insists that salvation is not simply a radically future experience but a thing of the present. So when Jesus proclaims to the repentant criminal, “Paradise . . . today,” we should take the pronouncement of salvation in terms of Luke’s consistent sense of immediacy. (Jerome Neyrey, The Passion According to Luke: A Redaction Study of Luke’s Soteriology [New York: Paulist Press, 1985],137-38)