Why are there differences in Luke chapter 7 and John chapter 12?

A:One of the differences is in the story of the woman bringing ointment in an alabaster box, to anoint Jesus. There are actually three versions of this story in the gospels.

Mark chapter 14 says a woman brought an alabaster box of ointment and anointed Jesus at the house of Simon the leper, late in the mission of Jesus.

Luke 7:36-50 says a sinful woman anointed the feet of Jesus from an alabaster box of ointment at the house of Simon, but this time Simon was a Pharisee rather than an outcast leper.

John 12:1-8 says that Mary, sister of Martha and Lazarus anointed the feet of Jesus with ointment at the start of the final week, but earlier than in Mark's Gospel.

Pope Gregory the Great decided in the sixth century that Mary, sister of Martha must be Mary Magdalene and that she and the sinful woman were the same person. Thus Mary Magdalene becomes a prostitute, or whore. This decision more or less brings the stories together, without really explaining the differences.

We know that the account in Luke is based on Mark's version, but the author chose to elaborate, making her a sinful woman, thus emphasising Jesus' message of forgiveness. We also know that John was loosely based on Luke, but John's theology is different to that of Luke and it gives the role of anointing Jesus to his friend Mary.