John's account of Jesus's death does not include many words spoken by Jesus; instead, most of the account is written in John's words. Twice John notes that what is happening is a direct fulfillment of Old Testament scripture: the soldiers casting lots for Jesus' robe and not one bone of Jesus' body being broken. John's gospel includes an incident in which Jesus commends his mother, Mary, into the care of a disciple. The soldiers give Jesus vinegar when he is thirsty, and soon Jesus (in John 19:30) says,
"It is finished."
This recounting of Jesus' death is quite short, only eight verses from the time Pilate signs off on Jesus' death to Jesus' final words.
Luke's account, on the other hand, is twenty-two verses long and includes no references at all to Old Testament prophecies. He does, however, include many more statements by Jesus. Luke describes the journey Jesus takes to Calvary through a crowd of both cheerers and mourners, and he spends much more time than John on the two other criminals who are hanging on the cross on either side of Jesus. He even includes the words Jesus spoke to the repentant criminal:
"Verily I say unto thee, today shalt thou be with me in paradise." (Luke 23:43)
Luke describes the taunting and mocking on more detail than John, but he does not even mention the soldiers who were breaking bones to hurry the process along (with Pilate's permission, of course). After Jesus dies, Luke's account is much more dramatic, including a thunderous black sky and a torn veil in the temple.
Each man writes what, for him, were the most significant moments of this significant event. Of course this means that they are likely to share different things, but as a whole, the two accounts are in alignment.