It is related from 'Umar Radiyallahu 'Anhu that Rasulullah Sallallahu Aayhi Wasallam said:
"Use olive oil in cooking and rubbing (on the body) because it is from a mubaarak tree". (IT)
English reference (IT): Book 25, Hadith 150 (IT)
Arabic reference (IT): Book 26, Hadith 158 (IT)