1 Then Jesus six days before the passover came to Bethany, where Lazarus was, which had been dead, whom he raised from the dead.
2 There they made him a supper; and Martha served: but Lazarus was one of them that sat at the table with him.

[There they made him a supper] Each Gospel has an account of a meal wherein Jesus was annointed, and there is much discussion regarding whether the descriptions are of the same or different events. My personal understanding is that Luke describes an event which took place early in Jesus ministry, likely while John the Baptist was still alive, while Matthew, Mark and John describe another occasion which occurred shortly before Jesus death. Compare Luke 7:36-50 with Matthew 26:6-13, Mark 14:3-9, and the account in this chapter.
On the first occasion the unnamed woman is described as a sinner and a question arises in the mind of the host, Simon, a pharisee, as to whether a true prophet would recognize and/or permit a sinner to have such personal contact with him. Jesus responded with a parable, then forgave the woman her sins.
The second occasion takes place in the house of Simon, the leper, in Bethany. This time the question raised is whether the expensive ointment would have been been put to better use by selling it and giving the money to the poor. Jesus defends the woman, Mary, the sister of Lazarus, and a devoted follower of Jesus, because she had been saving the ointment just for him. Think back to the parable on the first occasion. "Tell me, therefore, which of them will love him most?" ..."He to whom he forgave most."

3 Then took Mary a pound of ointment of spikenard, very costly, and anointed the feet of Jesus, and wiped his feet with her hair: and the house was filled with the odour of the ointment.

[Annointed the feet of Jesus] The custom of the time was for meals to be taken while lying on one's side on a short couch. The legs were too long for the couch so were generally folded back, behind the couch. A person standing behind the couch would have easy access to a celebrant's feet.

4 Then saith one of his disciples, Judas Iscariot, Simon's son, which should betray him,

[Judas Iscariot, Simon's son] Not necessarily the son of Simon the Leper, although that is not ruled out. Simon was a very popular name at that time (there were two Simons within the 12 desciples). Judas Iscariot is often described as Simon's son but the context does not identify of which Simon.

5 Why was not this ointment sold for three hundred pence, and given to the poor?
6 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.

[Not that he cared for the poor] The evangelist points out his false words.

[And bare what was put therein] Or rather, as some eminent critics contend, carried off, or stole what was put therein. The words of the Greek text are often used in this sense and the context supports that meaning here. Such a gift, turned over to his care, could be used by him to make up the shortage caused by his embezelment. John specifically stated that Judas was a thief.

7 Then said Jesus, Let her alone: against the day of my burying hath she kept this.

[Against the day of my burying] She had been keeping this most valuable posession for the day when it would be used to embalm Jesus body. Overwhelmed by love, she elected to use some of it to annoint him at this moment.

8 For the poor always ye have with you; but me ye have not always.

[But me ye have not always] The time of Jesus sacrificial death was drawing near.

9 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.
10 But the chief priests consulted that they might put Lazarus also to death;
11 Because that by reason of him many of the Jews went away, and believed on Jesus.

[that they might put Lazarus also to death] Now the plot becomes murderous. The chief priests could delude themselves into believing that Jesus was an imposter, deserving of death, but Lazarus had done nothing worthy of death. Murder was their plan.
As long as Lazarus lived they saw an incontestable proof of the Divine power of Christ. Many who come to see him through curiosity became converts to Christ through his testimony. He must be silenced.

12 On the next day much people that were come to the feast, when they heard that Jesus was coming to Jerusalem,
13 Took branches of palm trees, and went forth to meet him, and cried, Hosanna: Blessed is the King of Israel that cometh in the name of the Lord.

A great multitude of people from all points of the compass had gathered in Jerusalem for the Passover. Upon the raising of Lazarus, many become convinced that Jesus was the promised Messiah and welcomed him as the new king of Israel. They did not realize that Jesus, at this time, was "The Lamb of God, who taketh away the sin of the world." John 1:29. He would receive his kingdom at a later time. Use the Godsview search feature to follow "Lamb" through the Bible, especially the book of the Revelation.

14 And Jesus, when he had found a young ass, sat thereon; as it is written,
15 Fear not, daughter of Sion: behold, thy King cometh, sitting on an ass's colt.

After the ascension of Christ the disciples saw the meaning of many prophecies which referred to Christ, and applied them to him, which they had not fully comprehended before. Indeeed, it is only in the light of the new covenant that the old is fully understood.

17 The people therefore that was with him when he called Lazarus out of his grave, and raised him from the dead, bare record.
18 For this cause the people also met him, for that they heard that he had done this miracle.
19 The Pharisees therefore said among themselves, Perceive ye how ye prevail nothing? behold, the world is gone after him.

As our Lord's converts were rapidly increasing, the Pharisees thought it necessary to execute without delay what they had decided previously. Put Jesus to death. John 11:53.