Matthew, Mark, Luke, and John all tell the story of Jesus being anointed by a woman with oil (named Mary Magdelene in some accounts), and she is scolded for it (by Judas in John’s account), but some details don’t seem to harmonize across all four Gospel accounts. It seems that they are different events but with similar actions, or in the same event with conflicting details.

For the most part, they seem like the same event. Luke’s account, doesn’t even name the woman or specify the location (it just says at the house of “Simon the Pharisee”), so it seems the most out of sync. Matthew, and Mark, say that this event happens in Bethany and at the house of “Simon the Leper”. John doesn’t mention Simon the Leper he just says this is all happening at a dinner with Lazarus and his sisters Mary and Martha. One could argue that Lazarus, Martha, and Mary all lived with “Simon the Leper”. In John’s account, Mary is criticized by Judas specifically, but in Matt and Mark, the disciples are all guilty of criticizing Mary. Maybe Mark & Matthew either don’t know Mary’s critic is Judas or are just leaving his identity anonymous. Likewise, John is the only one that identifies the woman as Mary. Matt and Mark start off by saying it is two days before Passover, while John 12 seems to say it was six days. Could this be a simple error on Matthew/Mark or John’s part (or a later translation)? Or maybe Mary does the same thing twice, once in front of Lazarus where Judas criticizes her at Simon’s house, then four days later when the other disciples criticize her at a different location while Judas is elsewhere? Some have suggested that Lazarus is another name for “Simon the Leper” because, in the parable of the rich man and Lazarus in Luke 16:19-31, the man named Lazarus had a skin disease (presumable leprosy). I think all of these have problems and that the solution is that at least two or three out of four of them are separate events (Matthew and Mark are the same events).

Matthew 26:1-13 starts off with Jesus saying that there are two more days until Passover, and warning his disciples that will be killed soon. Meanwhile, the Pharisees were gathered together plotting to kill Jesus. Then the setting shifts to Jesus going to the home of Simon, a former leper, living in Bethany. While they were eating, a woman came in and anointed his head with expensive perfume. The disciples got upset about the perfume being wasted because it could have been given to the poor, but Jesus reprimanded them and said she was anointing him for his soon-coming burial. Mark 14:1-9 is the same story as Matthew, with minor distinctions like the narrator telling us that it was two days before Passover, and the fact that the oil was spikenard.

Luke 7:36-50, seems similar to the others, but it is quite different. The dinner host is Simon the Pharisee, and since he is a Pharisee, it is very unlikely that he was the same Simon who was recently healed of leprosy, from the Matthew and Mark accounts above. There is no indication that Simon was recently healed by Jesus. He shows no compassion for the woman and is disgusted by the idea of Jesus letting her touch him, which would imply he wasn’t recently healed of a disease that categorized him as unclean and untouchable until he was healed. Also, the city is not mentioned, so the setting may not be Bethany. In addition, the woman anointing Jesus is unnamed and simply categorized as a major sinner.

Furthermore, there is no mention of the disciples chastising her, only the judgmental thoughts of Simon the Pharisee. Simon is questioning why Jesus is allowing her, a sinful woman, to anoint and wash his feet with her hair, and tears. There is no mention of the perfume being poured on his head, nor does Jesus mention his burial. Jesus gave Simon a parable about a debtor who forgave two people each of their debts, one had a bigger debt, and the lesson was that the one with the bigger debt is more grateful. Likewise, the woman is thanking Jesus for forgiving her of her large debt (her sins). Jesus then tells him that she did things that he as the host should have done, like offering him water to wash his feet, greeting him with a kiss, and a cool wet cloth for his head, and other traditional hospitalities that were expected of the host in that culture. Jesus forgives her sins and she leaves, and some other men who are dinner guests grumble about his authority to forgive sins.

In John 12:1-11, things are more like Matthew and Mark’s account. The setting is Bethany, but it is six days before Passover, and Jesus is in the company of Lazarus (after he was raised) and his sisters, and there is no mention of Simon. John just says he was together with Lazarus, Martha, and Mary but he doesn’t what home they are in. Also, it is only Judas that criticized the woman. He was the disciples’ treasurer and was stealing from them as John (the author) points out, so he was a hypocrite since he didn’t care about giving the perfume money to the poor. He just wanted to steal his portion of it. Also, this woman is identified as Mary (the sister of Martha & Lazarus), and she is washing Jesus’s feet with her hair but there is no mention of her crying. Jesus’ response to Judas’ critique is the same as what he said to the disciples in Matthew and Mark’s account. John, like Mark, also mentions that the oil was spikenard.

One view some scholars have taken is that Matthew, Mark, and John are the same, and Luke is different. The location is not mentioned in Luke’s account so it’s possible the home of Simon the Pharisee is somewhere in Galilee, rather than Bethany. This is based on the preceding writing and the following events in Luke 7 (also in Matthew 11) which all happen in Galilee. The events prior to the anointing in Luke 7 are the same events in Matthew 11 where John the Baptist sends his disciples to ask if Jesus is the Messiah, which means John is alive at this time. So this can’t be the same dinner that happens after Jesus raised Lazarus, because that event happens right before Jesus was crucified, and John was executed by Herod Antipas over a year before the crucifixion of Jesus (Matthew 14:10, Mark 6:27, Luke 9:9). This means that the Luke dinner happens first, up to two years before the other accounts and since the disciples are not mentioned, so it may be that only Jesus is invited to Simon the Pharisee’s house and not his disciples. Luke’s gospel is built on eyewitness testimony (Luke 1:1-4) so he must have talked to someone who was there to get this specific information. In addition, Jesus talks directly to the woman and forgives her sins, and Simon the Pharisee is the only one mentioned having a problem with what she is doing, and there is no mention of the disciples. Plus the woman is unnamed and there is no mention of Jesus’ death or preparation for his burial, instead, he sees this as a form of the sin offering, asking for repentance. Notice that the woman from the Mark, Matthew, and John account does not cry during those dinners, so this is another distinction between her and the woman from Luke 7.

Looking at the other accounts, the perfume cost the same (300 denari) in Matthew, Mark, and John’s accounts. Mark & Matthew either don’t know the accuser is Judas or are just leaving his identity anonymous. Meanwhile, John reveals Judas as the accuser, which potentially shows this moment of Judas’ public embarrassment by Jesus. This could have been the initial motivation for (or the last straw leading to) his betrayal of Jesus. This suggests that the two days mentioned in Matthew and Mark are directed at the conversation within the Sanhedrin council as they plot to kill Jesus, rather than a reference to when the dinner happens which starts in Mark 14:3/Matthew 26:6. The setting at the beginning of the chapter in both versions talks about the plot to kill Jesus by the Sanhedrin. Then Judas shows up to meet with the Sanhedrin as they are discussing this. Judas’ appearance before the Sanhedrin to betray Jesus for the 30 pieces of silver, isn’t mentioned until after the dinner (Matt 26:14-16 & Mark14:10-11). The dinner scene of these two accounts (Matt 26:6-13 & Mark 14:3-9) disrupts the story of Juda’s betrayal. So it’s possible that the authors are placing the dinner scene here as a flashback showing why Judas reached out at this point to betray Jesus. This would allow for the dinner to be six days before Passover, but the betrayal meeting four days later. That would explain why there is no mention of Judas betraying in John 12, just the diner where Judas gets embarrassed. Luke’s gospel has the betrayal meeting taking place in Luke 22:1-6 but the dinner at Bethany is not mentioned at all, which means these are two separate events, which could comply that while Judas is the connecting thread, they happened at different times.

One potential question that remains is that Matthew and Mark’s account happened at Simon the Leper’s house, and there is no mention of Lazarus and his sisters, while John’s account simply says that they were with Lazarus’ family. Some modern translations say the setting of the dinner in John 12 is Lazarus’ house, but the word house oikia (οἰκία) is not there in the greek text like it is in Matt and Mark, so he doesn’t truly say it was Lazarus’ house. However, a simple solution is that Simon the Leper invited Lazarus and his sisters to the dinner and Martha agreed that she and Mary would help prepare and serve the food. All three accounts are in Bethany so it’s easy to imagine they all knew each other. Lastly, this would mean Jesus’ head (according to Matt & Mark) and feet (according to John) were anointed and washed by Mary with her hair. In conclusion, the dinner event happens six days before Passover, it is Mary who anoints Jesus, Judas scolds her, Jesus condemns him, and Judas who was embarrassed at the dinner went to the Sanhedrin Council to betray Jesus four days later. Matt and Mark placed this dinner in the midst of Judas’ betrayal story to show his motive. Meanwhile, Luke’s account is a separate dinner altogether with a Pharisee named Simon, involving a different unknown woman.

Alternative theory:
Apologetics ministry Answers in Genesis (linked below), presents various possibilities including a version of the preceding theory. In addition, they present a scenario of three distinct events. With this theory, the John 12 dinner happens when Jesus arrives in Jerusalem for “Palm Sunday”, (the Sunday before Resurrection Day), because it is six days before Passover, meanwhile, the Matthew 26 and Mark 14 dinners are four days later (two days before Passover). In John, they are at Lazarus’ house or somewhere separate from Simon the Leper’s home, and only Judas has a problem with the oil being used on Jesus by Mary. In Matt and Mark, all the disciples have a problem with the perfume’s waste simply parroting what Judas said previously without learning the lesson of Jesus’ initial response. Judas is either anonymous, silent, or not present at this dinner. Judas meets with the Pharisees to betray Jesus, maybe this explains his absence at the dinner in Matt and Mark’s account. The woman (who is unnamed) only anoints Jesus’ head and not his feet, but she doesn’t use her hair at all. Unlike Mary from John 12:3 who uses her hair. Luke’s dinner account is separate because it is a completely separate event that occurred back when John the Baptist was still alive. To conclude, the John dinner happens six days before Passover, at Lazarus’ home (or somewhere other than Simon’s house), and his sister Mary is the one pouring out the spikenard. Then four days later while the Pharisees are plotting to kill Jesus, the Matthew/Mark dinner happens and the disciples are repeating what Judas said a few days before in response to the wasting of perfume but this time towards a different unnamed woman who is repeating what Mary did but without using her hair. Meanwhile, Judas is either silent and meets with Sanhedrin later or he is absent because he is meeting with them during the dinner.

Resources:
Answers in Genesis article on this subject

An excerpt from the wiki page on Simon the Leper:
“Because of some similarities, efforts have been made to reconcile the events and characters, but some scholars have pointed out differences between the two events.[7] An alternative explanation for the similarities is that the Luke 7 anointing and the anointing at Bethany[8][9][10] happened with some of the same participants, but several years apart.[11] Simon the Leper is also sometimes identified as the same person as Lazarus of Bethany or identified as his father or brother[citation needed]. This is because Matthew and Mark mention Simon, while John mentions Lazarus, but all four gospels assume one lodging at Bethany during the last week. Abbé Drioux identified all three as one: Lazarus of Bethany, Simon the Leper of Bethany, and the Lazarus of the parable, on the basis that in the parable Lazarus is depicted as a leper, and due to a perceived coincidence between Luke 22:2 and John 12:10—where after the raising of Lazarus, Caiaphas and Annas tried to have him killed. More on Simon the Leper Wiki.