Augustine of Hippo — as excerpted in the Catena Aurea on John 12:1-11

“(Tr. li. 6) 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. Πίστις is Greek for faith. Dost thou seek to do justice? The just liveth by faith. (Heb. 10:38) Anoint the feet of Jesus by good living, follow the Lord’s footsteps: if thou hast a superfluity, give to the poor, and thou hast wiped the Lord’s feet; for the hair is a superfluous part of the body.”