Monday of Holy Week brings us to the anointing of Jesus at Bethany. He must be anointed, because he is to be a king and will soon reign from the throne of the Cross. Recall the charge against him, "Jesus of Nazareth, the King of the Jews."
The kings of Israel, and of the ancient near east generally, were always anointed with oil. But there are two aspects of Jesus' anointing that make it special. First, in every account we have, he is anointed by a woman. Typically, the kings of Israel were anointed by someone with authority, like a prophet or priest. In contrast, Jesus' royal anointing comes from someone without authority, with a lesser place in society. It is the poor and oppressed who can recognize the Lord in the world, and everyone else when they can at least admit of their inner poverty and vulnerability.
Second, at least in Luke and John's versions, Jesus is anointed on his feet. Kings were anointed on their heads. The kingdom of Jesus will be one of service and humility, not power and authority.