John 12:4

But Judas Iscariot, one of his disciples that should betray him, saith, Why was not this ointment sold for three hundred shillings, and given to the poor?

Matthew and Mark record this anointing, in which it seemed to have occurred on Tuesday or Wednesday of the following week, Matthew making it the incident that triggered the betrayal of Jesus by Judas. All the Gospel accounts place it in the last week of the ministry; and while John's account SEEMS to say it was on Friday, it is not SO STATED. His words are, "They made him a supper THERE (not THEN)." Robertson and most harmonizers place the event in the sequence mentioned by Matthew and Mark, construing John as slightly unchronological here.

In Matthew and Mark, it is the "disciples" who complained of the waste of the nard; in John, the center of the objection is revealed as Judas. This is the kind of "contradiction" so delighted in by critics. Judas, of course, had persuaded other disciples to go along with his objection, Matthew himself probably having been one that did; and thus it would have been improper for Matthew to have laid all the blame on Judas for something he participated in. Note too that John did not say that Judas ALONE objected. Where, then, is the contradiction? It isn't.

Three hundred shillings ... The word in the Greek (shilling) denotes a coin worth about eight pence half-penny, or nearly seventeen cents.[6] The relative value of the coin appears in the fact of its being a day's wages (Matthew 20:9), making the value of the nard to have been the amount of money a man might have earned for three hundred days of labor.