It was two days before Passover and the Festival of Unleavened Bread. The chief priests and legal experts through cunning tricks were searching for a way to arrest Jesus and kill him.
But they agreed that it shouldn't happen during the festival; otherwise, there would be an uproar among the people.
Jesus was at Bethany visiting the house of Simon, who had a skin disease. During dinner, a woman came in with a vase made of alabaster and containing very expensive perfume of pure nard. She broke open the vase and poured the perfume on his head.
Some grew angry. They said to each other, "Why waste the perfume?
This perfume could have been sold for almost a year's pay and the money given to the poor." And they scolded her.
Jesus said, "Leave her alone. Why do you make trouble for her? She has done a good thing for me.
You always have the poor with you; and whenever you want, you can do something good for them. But you won't always have me.
She has done what she could. She has anointed my body ahead of time for burial.
I tell you the truth that, wherever in the whole world the good news is announced, what she's done will also be told in memory of her."
Judas Iscariot, one of the Twelve, went to the chief priests to give Jesus up to them.
References for Mark 14:10
When they heard it, they were delighted and promised to give him money. So he started looking for an opportunity to turn him in.