Some people point out that to have the comma after today in Luke 23:43 is linguistically incorrect. That may be true for English but Luke used many Hebrew idioms as he wrote his text in Greek which has no such grammatical rule. The Jewish practice of joining the word “today” to the preceding verb, when closing or introducing a statement, is a Semetic idiom. They did this to add significance to the statement made, or that would follow. Many examples of this can be found. In Deuteronomy 9:1 the Isrealites are told they would be crossing the Jordan river today, but in actuality they didn’t cross for a couple of months. The word today was used for emphasis, just as Jesus did when he spoke to the thief beside him.
Deuteronomy 9:1 Tree of Life Version
9 “Hear, O Israel! You are about to cross over the Jordan today, to go in to dispossess nations greater and mightier than yourself—cities great and fortified up to the heavens.
Deuteronomy 8:19 Easy-to-Read Version
19 “Don’t ever forget the Lord your God. Don’t ever follow other gods or worship and serve them. If you do that, I warn you today: You will surely be destroyed!
Deuteronomy 28:13 Christian Standard Bible
13 The Lord will make you the head and not the tail; you will only move upward and never downward if you listen to the Lord your God’s commands I am giving you today and are careful to follow them.
Deuteronomy 11:26 English Standard Version Anglicised
26 “See, I am setting before you today a blessing and a curse:
Deuteronomy 7:11 Contemporary English Version
11 So be sure to obey his laws and teachings I am giving you today.
Most translations of the Greek texts put the comma before the word today and so the debates between those interested go back and forth and on and on. Maybe a good way to decide where the comma should go would be to pay close attention to the conversation between Jesus and the thief. What did the thief specifically ask of Jesus?
What words did Jesus reply? Did the thief ask for forgiveness? Did Jesus promise him he would be in heaven?
Luke 23:42-43 New American Bible (Revised Edition)
42 Then he said, “Jesus, remember me when you come into your kingdom.” 43 He replied to him, “Amen, I say to you, today you will be with me in Paradise.”