John 12:3
Then Mary took a pound of very costly oil of spikenard, anointed the feet of Jesus, and wiped His feet with her hair. And the house was filled with the fragrance of the oil.

I have heard many theories surrounding this incident.
Here is what I know and gather.
First, Mary probably feels she owes Jesus some great appreciation for raising her brother from the dead. She wants to honor him somehow.
Second, the spikenard was not cheap. Judas suggested the selling price of 300 denarii or a year’s wages.
Third, Jesus said she did this to prepare Him for burial.

I have read that perhaps she took her own anointing oil for her own future burial and used it on the Savior.
Perhaps this was a gift to her or the family.
No matter. She honored Jesus in the best way possible.

What will you give to honor Jesus?