An idiom is an expression that cannot be deciphered merely by knowing the individual meanings of the words, but requires a cultural context. The idiomatic term, "This day," or "Today," does not mean a 24 period, but is an intensifier of gravity or solemnity. Jesus Christ used the expression "today" to the thief on the cross in Luke 23:42-43 to emphatically express a promise that would eventually take place. Jesus Himself did not go to paradise that very day. The solemn promise Jesus made was for a future time when the thief, as well other repentant sinners, would be resurrected and remembered by Christ.