Chapter 12 of St John's Gospel opens with the story of St Mary Magdalene anointing Christ's feet with expensive oil. This passage has long been a rich source for mystical interpretations.
You can find the Greek, Latin and Knox translations over at New Advent. And you can listen to the Latin and the Greek.
1 Jesus ergo ante sex dies Paschæ venit Bethaniam, ubi Lazarus fuerat mortuus, quem suscitavit Jesus. 2 Fecerunt autem ei cœnam ibi, et Martha ministrabat, Lazarus vero unus erat ex discumbentibus cum eo. 3 Maria ergo accepit libram unguenti nardi pistici pretiosi, et unxit pedes Jesu, et extersit pedes ejus capillis suis: et domus impleta est ex odore unguenti. 4 Dixit ergo unus ex discipulis ejus, Judas Iscariotes, qui erat eum traditurus: 5 Quare hoc unguentum non veniit trecentis denariis, et datum est egenis? 6 Dixit autem hoc, non quia de egenis pertinebat ad eum, sed quia fur erat, et loculos habens, ea quæ mittebantur, portabat. 7 Dixit ergo Jesus: Sinite illam ut in diem sepulturæ meæ servet illud. 8 Pauperes enim semper habetis vobiscum: me autem non semper habetis.
 Jesus therefore, six days before the pasch, came to Bethania, where Lazarus had been dead, whom Jesus raised to life.  And they made him a supper there: and Martha served: but Lazarus was one of them that were at table with him.  Mary therefore took a pound of ointment of right spikenard, of great price, and anointed the feet of Jesus, and wiped his feet with her hair; and the house was filled with the odour of the ointment.  Then one of his disciples, Judas Iscariot, he that was about to betray him, said:  Why was not this ointment sold for three hundred pence, and given to the poor?  Now he said this, not because he cared for the poor; but because he was a thief, and having the purse, carried the things that were put therein.  Jesus therefore said: Let her alone, that she may keep it against the day of my burial.  For the poor you have always with you; but me you have not always.
This is a time of preparation for the feast of the Passover, and for Christ's suffering and death:
ALCUIN. As the time approached in which our Lord had resolved to suffer, He approached the place which He had chosen for the scene of His suffering: Then Jesus six days before the passover came to Bethany. First, He went to Bethany, then to Jerusalem; to Jerusalem to suffer, to Bethany to keep alive the recollection of the recent resurrection of Lazarus; Where Lazarus was, which had been dead, whom He raised from the dead.
THEOPHYL. On the tenth day of the month they took the lamb which was to be sacrificed on the passover, and from that time began the preparation for the feast. Or rather the ninth day of the month, i.e. six days before the passover, was the commencement of the feast. They feasted abundantly on that day.
Thus we find Jesus partook of a banquet at Bethany: There they made Him a supper, and Martha served. That Martha served, shows that the entertainment was in her house. See the fidelity of the woman: she does not leave the task of serving to the domestics, but takes it upon herself. The Evangelist adds, in order, it would seem, to settle Lazarus, resurrection beyond dispute, But Lazarus was one of them that sat at the table with Him.
AUG. He lived, talked, feasted; the truth was established, the unbelief of the Jews confounded.
Mary's focus is on Jesus alone:
CHRYS. Mary did not take part in serving the guests generally, but gave all her attention to our Lord, treating Him not as mere man, but as God: Then took Mary, a pound of spikenard, very costly, and anointed the feet of Jesus, and wiped His feet with her hair.
AUG. The word pistici seems to be the name of some place, from which this precious ointment came.
ALCUIN. Or pistici means genuine, non-adulterated. She is the woman that was a sinner, who came to our Lord in Simon's house with the box of ointment.
AUG. That she did this on another occasion in Bethany is not mentioned in Luke's Gospel, but is in the other three. Matthew and Mark say that the ointment was poured on the head, John says, on the feet. Why not suppose that it was poured both on the head, and on the feet? Matthew and Mark introduce the supper and the ointment out of place in the order of time (Matt 26:9 and Mark 14:3). When they are some way farther on in their narration, they go back to the sixth day before the passover.
And the house was filled with the odor of the ointment.
AUG. Remember the Apostle's words: To the one we are the savor of death unto death; and to the other the savor of life unto life (2 Cor 11:16).
Jesus condemns an undue focus on the poor at the expense of God:
AUG. Then said one of His disciples, Judas Iscariot, Simon's son, which should betray Him,
Why was not this ointment sold for three hundred pence, and given to the poor? In the other Gospels it is the disciples who murmured at the waste of the ointment. I think myself that Judas is put for the whole body of disciples; the singular for the plural. But at any rate we may supply for ourselves, that the other disciples said it, or thought it, or were persuaded by this very speech of Judas.
The only difference is, that Matthew and Mark expressly mention the concurrence of the others, whereas John only mentions Judas, whose habit of thieving He takes occasion to notice: This he said, not that he cared for the poor, but because he was a thief, and had the bag, and bare what was put therein.
ALCUIN. He carried it as a servant, he took it out as a thief.
AUG. Judas did not perish at the time when he received money from the Jews to betray our Lord. He was already a thief, already lost, and followed our Lord in body, not in heart; wherein we are taught the duty of tolerating wicked men, lest we divide the body of Christ.
He who robs the Church of anything may be compared to the lost Judas. Tolerate the wicked, you that are good, that you may receive the reward of the good, and not fall into the punishment of the wicked. Follow the example of our Lord's conversation upon earth. Wherefore had He bags, to whom the Angels ministered, except because His Church should afterwards have bags?
Why did He admit thieves, but to show that His Church should tolerate thieves, while it suffered from them. It is not surprising that Judas, who was accustomed to steal money from the bags, should betray our Lord for money.
CHRYS. But why was a thief entrusted with the bags of the poor? Perhaps it was to give him no excuse of wanting), money, for of this he had enough in the bag for all his desires.
THEOPHYL. Some suppose that Judas had the keeping of the money, as being the lowest kind of service. For that the ministry of money matters ranks below the ministry of doctrine, we know from what the Apostle says in the Acts, It is not reason that we should leave the word of God, and serve tables (Acts 6:2).
CHRYS. Christ, with great forbearance, does not rebuke Judas for his thieving, in order to deprive him of all excuse for betraying Him.
CHRYS. Again, as if to remind His betrayer, He alludes to His burial; For the poor you have always with you, but Me you have not always: as if He said, I am a burden, a trouble to you; but wait a little, and I shall be gone.
AUG. He was speaking of His bodily presence; for in respect of His majesty, providence, ineffable and invisible grace, those words are fulfilled, Lo, I am with you always, even to the end of the world (Matt 28:20). Or thus: In the person of Judas are represented the wicked in the Church; for if you are a good man, you have Christ now by faith, and the Sacrament, and you shall have Him always, for when you have departed hence, you shall go to Him who said to the thief, Today shall thou be with Me in paradise (Luke 23:43).
But if you are wicked, you seem to have Christ, because you are baptized with the baptism of Christ, because you approach to the altar of Christ: but by reason of your wicked life, you shall not have Him always. It is not you (singular) have, but you (plural) have, the whole body of wicked men being addressed in Judas.
Much people of the Jews therefore knew that He was there, and they came not for Jesus' sake only, but that they might see Lazarus also, whom He had raised from the dead. Curiosity brought them, not love.
The mystical meaning of the ointment:
ALCUIN. Then said Jesus, Let her alone: against the clay of My burying has she kept this: meaning that He was about to die, and that this ointment was suitable for His burial. So to Mary who was not able to be present, though much wishing, at the anointing of the dead body, was it given to do Him this office in His lifetime.
AUG. The ointment with which Mary anointed the feet of Jesus was justice. It was therefore a pound. It was ointment of spikenard (pistici) too very precious. Greek for faith. Do you seek to do justice? The just live by faith
(Heb 10:38). Anoint the feet of Jesus by good living, follow the Lord's footsteps: if you have a superfluity, give to the poor, and you have wiped the Lord's feet; for the hair is a superfluous part of the body.
ALCUIN. And observe, on the first occasion of her anointing, she anointed His feet only, but now she anoints both His feet and head. The former denotes the beginnings of penitence, the latter the righteousness of souls perfected. By the head of our Lord the loftiness of His Divine nature, by His feet the lowliness of His incarnation are signified; or by the head, Christ Himself, by the feet, the poor who are His members.
AUG. The house was filled with the odor; the world was filled with the good fame.