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". (FR)
English reference (FR): Book 25, Hadith 150 (FR)
Arabic reference (FR): Book 26, Hadith 158 (FR)