John Gill

Then took Mary a pound of ointment of spikenard very costly,.... Worth three hundred pence, according to Judas's estimation of it. This Mary was the other sister of Lazarus; See Gill on Mat 26:7, See Gill on Mar 14:3, concerning the nature and value of this ointment: and anointed the feet of Jesus; as he lay upon the bed or couch, at supper: and wiped his feet with her hair; See Gill on Luk 7:38. And the house was filled with the odour of the ointment; see Sol 1:3; ointment of spikenard was very odoriferous: this may be an emblem of the sweet savour of Christ, in the ministration of the Gospel, throughout the whole world.