11: Jesus sets forth a very important principle here, which could easily be missed. It is not enough to do good for the sake of doing good. One must do good because of he who is good. Good is to be done to one’s fellow because he is the creation of God, who is good. Good done only for the sake of good alone will ultimately find its meaning defined by the doer, which makes the deed no better or worse than he. Human beings, left to themselves, doing good only as they define it will ultimately create the most horrific form of evil. Judas could now attest to this truth, though he was unaware of it at the time.
Mary did good for Christ because he has done good for us all.
12: Whether Mary fully realized or understood what Jesus said her purpose was has been the target of speculation. However, Jesus clearly states her intentions, and it is best to take his word for it. The use of ointment for the burial of the dead was common. None would have denied this. It seems likely that those present would have taken Jesus seriously, even if they did not realize the implications of his statement.